Suggestive Case of Viral-Induced Chondrosarcoma (Chondrogenic Neoplasia) in Largescale Mullet, Planiliza macrolepis (Smith, 1846) from the Pondicherry, Southeast Coast of India

Suggestive Case of Viral-Induced Chondrosarcoma (Chondrogenic Neoplasia) in Largescale Mullet, Planiliza macrolepis (Smith, 1846) from the Pondicherry, Southeast Coast of India | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Suggestive Case of Viral-Induced Chondrosarcoma (Chondrogenic Neoplasia) in Largescale Mullet, Planiliza macrolepis (Smith, 1846) from the Pondicherry, Southeast Coast of India Vasanthan Koothan, Ayyaru Gopalakrishnan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8685456/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Neoplasia in wild fish populations is increasingly recognized as an important indicator of environmental stress and ecosystem health. The present study reports the first documented case of suggestive chondrosarcoma (chondrogenic neoplasia) in the largescale mullet Planiliza macrolepis (Smith, 1846) from the southeast coast of India. An adult female specimen exhibiting a conspicuous external mass near the caudal peduncle was collected from the Pondicherry fish landing center during a routine survey. Gross examination revealed a firm, irregular, pinkish-white tumorous growth measuring approximately 3.0 × 3.1 × 3.2 cm. Histopathological analysis demonstrated a malignant cartilaginous neoplasm characterized by abundant chondroid matrix, marked hypercellularity, nuclear pleomorphism, hyperchromasia, frequent binucleation, and chondrocyte-like cells within well-defined lacunae. Histochemical staining with Alcian Blue (pH 2.5) and Toluidine Blue confirmed the cartilaginous nature of the extracellular matrix. Ultrastructural examination using transmission electron microscopy revealed the presence of virus-like particles within the cytoplasm of neoplastic cells, suggesting a possible viral involvement in tumor development. Chondrosarcoma is exceedingly rare in teleost fishes, and this finding expands the known host range of malignant chondrogenic tumors in aquatic vertebrates. The present case highlights the need for continued surveillance of neoplastic diseases in marine fishes and underscores the potential role of infectious agents and environmental stressors in tumorigenesis within coastal ecosystems. Chondrosarcoma Chondrogenic neoplasia Planiliza macrolepis Fish neoplasia Figures Figure 1 Figure 2 Figure 3 Figure 4 INTRODUCTION The largescale mullet ( Planiliza macrolepis ) is a member of the Mugilidae family and is commonly found in coastal and estuarine waters across the Indo-Pacific region (Whitfield et al. 2012 ). This fish species is distinguished by its streamlined, elongated body and conspicuously large scales. Individuals can grow up to approximately 50 cm (20 inches) in length. Its silvery-gray body, which fades to a lighter tone on the underside, serves as effective camouflage within its aquatic habitat. Mature fish are predominantly herbivorous, consuming algae and organic detritus, and typically form shoals an adaptive behavior that enhances protection against predators. P. macrolepis is ecologically important for nutrient cycling in coastal ecosystems and economically valuable as a reliable food source. It supports both artisanal and commercial fisheries, providing sustenance and income for coastal communities across the Indo-Pacific region. Tumor development, or neoplasia, is well-documented in fish and follows classification patterns similar to those in higher vertebrates (Knusel et al. 2007; Hochwartner et al. 2010 ). In India, an increasing number of neoplastic conditions have been documented in marine fishes, and these lesions are widely regarded as important biological indicators of environmental stressors, including pollution and the emergence of infectious diseases (Chavan et al. 2009 ; Gopalakrishnan et al. 2011 ; Sinduja et al. 2013 ; Sinduja et al. 2014 ; Vijayakumar et al. 2014 ; Singaravel et al. 2015 ; Vijayakumar et al. 2015 ; Singaravel et al. 2016 a-e; Vijayapoopathi et al. 2016 ; Vinothkumar et al. 2017 ; Singaravel et al. 2017 ; Singaravel et al. 2018 ; Mariasingrayan et al. 2024 ; Singaravel and Gopalakrishnan 2025 ; Mariasingarayan et al. 2025 ; Koothan et al. 2026a , b ). The occurrence of tumours in wild fish populations has been linked to multiple etiological factors, such as exposure to chemical pollutants, genetic susceptibility, prolonged inflammatory processes, and infectious agents, with particular emphasis on oncogenic viruses (Zhou et al. 2010; Coffee et al. 2013; Li 2014; Vijayakumar et al. 2014 ; Duis and Coors 2016; Carolin et al. 2017; Singaravel et al. 2018 ; Hader et al. 2020; Baines et al. 2021; Singaravel and Gopalakrishnan 2025 ). Chondrosarcoma is a malignant cartilage-forming neoplasm characterized by the production of chondroid matrix by neoplastic chondrocytes and represents one of the most common primary cartilaginous tumours (Lokuhetty et al. 2020 ; Weinschenk et al. 2021 ). Histologically, it is defined by increased cellularity, nuclear atypia, hyperchromasia, frequent binucleation, and an infiltrative growth pattern within hyaline or myxoid cartilage. Chondrosarcomas exhibit considerable morphological and biological heterogeneity and are commonly classified based on histological grade, which correlates with tumour aggressiveness and prognosis. While extensively studied in terrestrial vertebrates, particularly in humans and domestic animals, chondrosarcoma is infrequently reported in fishes, and its pathogenesis, biological behaviour, and etiological factors in aquatic species remain poorly understood. Chondrogenic tumours have been previously reported in fishes (Mesbah et al. 2016 ; Sirri et al. 2009 , 2010 ). Among these, chondrosarcoma represents a malignant and more specific chondrogenic neoplasm and was first identified in fish in species such as the paddlefish Polyodon spathula (Bean-Knudsen et al. 1987 ). However, documentation of chondrogenic -chondrosarcoma in other fish species remains extremely limited. The present study reports the first documented case of chondrogenic-chondrosarcoma in the largescale mullet Planiliza macrolepis , thereby expanding the known host range of this rare malignant chondrogenic tumour in teleost fishes. MATERIALS AND METHODS Sample Collection During a routine biological sample survey conducted under a Ministry of Earth Sciences, Government of India-sanctioned project under Deep Ocean Mission (DOM). an adult female largescale mullet ( Planiliza macrolepis ) exhibiting signs of external tumour development was collected in August 2025. The specimen was procured from the Pondicherry fish market, located along the southeast coast of India. The fish weighed 760 g and measured 44 cm in total length, and showed conspicuous abnormal growths near the caudal peduncle. Owing to this unusual presentation, the specimen was selected for detailed laboratory analysis. Gross Pathological Examination A macroscopic assessment was performed to record the tumor's size, shape, surface characteristics, coloration, and consistency. The mass was carefully excised and its dimensions (length, width, and height) were recorded. High-quality photographs were taken under controlled lighting to document external features and any notable variations in appearance, such as discoloration or texture. Histological Analysis The tumour tissue samples were excised and fixed for 24 h in 10% neutral buffered formalin (NBF) solution, followed by several washes in tap water prior to dehydration through a graded alcohol series, cleared in xylene, and embedded in paraffin wax. Thin sections (5 µm) were prepared using a rotary microtome (LEICA RM2125 RTS) and stained with haematoxylin and eosin (Coolidge and Howard 1979). Additional sections were stained with Alcian Blue (pH 2.5) and Toluidine Blue. The stained tissue sections were examined under a light microscope (LEICA DM 2500 LED). Transmission Electron Microscopy (TEM) Tumor tissue was aseptically excised and fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4) for 24 hours, followed by post-fixation in 1% osmium tetroxide for 3 hours. After dehydration through an ascending ethanol series, tissues were embedded in Epon resin. Semi-thin sections were stained with toludine blue, while ultra-thin sections were stained with uranyl acetate and lead citrate. Samples were observed under a Philips Tecnai T12 Spirit TEM operating at 80 kV to analyze ultrastructural features. RESULT Gross Pathology External examination of the affected P. macrolepis specimen revealed a prominent mass located near anterior to the caudal fin, extending across both the dorsal and ventral surfaces of the tail region. The tumor measured approximately 3.0 × 3.1 × 3.2 cm and exhibited a firm, rigid consistency. It presented as an irregularly spherical mass with a distinct pinkish-white coloration, suggestive of potential underlying tissue changes or vascular alterations (Fig. 1 ). Histopathology Histological examination of haematoxylin and eosin-stained sections revealed a neoplastic lesion composed of abundant chondroid matrix with numerous chondrocyte-like cells embedded within well-defined lacunae (Fig. 2 A&B). The tumour showed increased cellularity with irregular clustering of cells. Neoplastic chondrocytes exhibited moderate to marked nuclear pleomorphism, hyperchromasia, and frequent binucleation; occasional multinucleated cells were also observed, while mitotic figures were rare. Toluidine Blue-stained sections demonstrated pronounced metachromasia of the extracellular matrix, confirming the presence of a chondroid matrix (Fig. 3 A&B). Alcian Blue (pH 2.5) staining showed strong and diffuse positivity of the tumour matrix, indicating abundant acidic mucopolysaccharides and sulfated glycosaminoglycans characteristic of cartilaginous tissue (Fig. 3 C&D). Transmission Electron Microscopy Ultrastructural analysis of tumor tissue revealed numerous virus-like particles (VLPs) within the cytoplasm of affected cells. These particles were spherical to polyhedral in shape, ranging from 200 to 250 nm in diameter. Each VLP exhibited a distinct nucleocapsid enclosed by an electron-dense protein capsid. The viral particles were distributed throughout the cytoplasm, indicating potential viral involvement in tumor pathogenesis (Fig. 4 ). DISCUSSION Neoplasia has been documented across a broad phylogenetic spectrum of fishes and virtually all organ systems, reflecting both the evolutionary antiquity of tumorigenesis and the susceptibility of aquatic vertebrates to diverse carcinogenic influences (Wellings 1969 ; Roberts 2012 ). The etiology of fish tumors is widely regarded as multifactorial, involving complex interactions between environmental contaminants, genetic predisposition, age, sex, chronic tissue irritation, and infectious agents, particularly oncogenic viruses (Vielkind & Vielkind 1982 ; Anders & Yoshimizu 1994 ; Okihiro et al. 1993 ). In recent decades, the increasing frequency of tumor reports in wild marine fishes from Indian coastal waters has highlighted neoplasia as a valuable biological indicator of ecosystem health and environmental stress (Chavan et al. 2009 ; Gopalakrishnan et al. 2011 ; Singaravel et al. 2016 a–e; Vinothkumar et al. 2017 ; Mariasingrayan et al. 2024 ). The present study documents a rare chondrogenic malignancy in the largescale mullet Planiliza macrolepis , a widely distributed and ecologically important mugilid species (Whitfield et al. 2012 ). Grossly, the tumor presented as a firm, irregular, pinkish-white mass located near the caudal peduncle, a morphology comparable to previously described chondrogenic neoplasms in fishes, including cranial chondrosarcoma in paddlefish ( Polyodon spathula ) (Bean-Knudsen et al. 1987 ) and chondromas in grass carp and neon tetra (Sirri et al. 2009 , 2010 ; Mesbah et al. 2016 ). The size, rigidity, and invasive appearance of the lesion in the present case are consistent with malignant behavior rather than a benign cartilaginous proliferation. Histopathological evaluation provided definitive evidence supporting a diagnosis of chondrosarcoma. The tumor was characterized by abundant chondroid matrix containing densely packed neoplastic chondrocytes within lacunae, marked hypercellularity, nuclear pleomorphism, hyperchromasia, and frequent binucleation. These features are in agreement with the diagnostic criteria for chondrosarcoma described in the WHO Classification of Tumours of Soft Tissue and Bone (Lokuhetty et al. 2020 ) and with clinicopathological descriptions in higher vertebrates (Weinschenk et al. 2021 ; Lam et al. 2019 ). Although mitotic figures were infrequent, this finding does not preclude malignancy, as low mitotic activity has also been reported in conventional chondrosarcomas with infiltrative growth and aggressive potential (Depboylu et al. 2023 ). Chondrogenic tumors are exceedingly uncommon in teleost fishes, and most reported cases are benign chondromas rather than malignant chondrosarcomas (Sirri et al. 2009 , 2010 ; Mesbah et al. 2016 ). To date, chondrosarcoma has been documented only sporadically in fishes, notably in paddlefish (Bean-Knudsen et al. 1987 ). Therefore, the present report represents the first confirmed case of chondrosarcoma in Planiliza macrolepis and expands both the taxonomic and anatomical spectrum of malignant cartilaginous tumors in teleosts. Mugilid fishes are known to develop a variety of neoplasms, including squamous cell carcinoma (Jithendran et al. 2011 ), myxoinflammatory fibroblastic sarcoma, leiomyoma (Singaravel et al. 2016 b), and cutaneous fibroma (Mariasingrayan et al. 2024 ). However, cartilaginous malignancies have not previously been reported in this group. The present finding therefore underscores the neoplastic diversity observed in mullets and suggests that mugilids may be more susceptible to mesenchymal tumors than previously recognized. A particularly noteworthy aspect of this study is the ultrastructural detection of virus-like particles (VLPs) within the cytoplasm of neoplastic cells. Viral involvement in fish tumorigenesis has been well documented, especially in epidermal papillomas, lymphocystis, and chromatophoromas (Anders & Yoshimizu 1994 ; Okihiro et al. 1993 ; Vijayapoopathi et al. 2016 ). The presence of VLPs in the present case raises the possibility of a viral role in the initiation or progression of chondrosarcoma in P. macrolepis . While causality cannot be established based solely on ultrastructural observations, similar associations between viral particles and neoplastic tissues have been reported in other fish tumors, supporting a viral oncogenesis hypothesis (Anders & Yoshimizu 1994 ; Roberts 2012 ). The increasing number of tumor reports from Indian coastal waters, including melanophoromas, chromatophoromas, fibrosarcomas, odontomas, and various epithelial and mesenchymal neoplasms (Singaravel et al. 2015 , 2016 d, 2017; Vijayakumar et al. 2014 , 2015 ; Koothan et al. 2026a , b ), suggests that environmental stressors such as pollution, habitat degradation, and pathogen emergence may play an important role in tumor development. Given the ecological and commercial significance of P. macrolepis , the occurrence of a malignant tumor in a wild individual is of concern and warrants further epidemiological and molecular investigations. In conclusion, this study provides the first evidence of chondrosarcoma in the largescale mullet Planiliza macrolepis and adds to the limited global literature on malignant chondrogenic tumors in fishes. The combined gross, histopathological, histochemical, and ultrastructural findings strongly support the diagnosis and suggest a possible viral contribution to tumor pathogenesis. Continued surveillance of neoplastic diseases in wild fish populations, coupled with advanced molecular diagnostics, is essential for understanding tumor etiology, assessing environmental health, and safeguarding fishery resources. Declarations Conflict of Interest The authors declare that there is no conflict of interest related to the publication of this Ethics Statement The manuscript does not require ethical approval. According to the guidelines framed by the Government of India for experiments on fish (CPCSEA), ethical approval is required only for experimental studies and wild fishes, not for research involving dead food fish obtained from such landing sites. Funding The authors gratefully acknowledge the Ministry of Earth Sciences, Government of India, for the financial support provided under the Deep Ocean Mission (DOM) for the project entitled “Prevalence of emerging Viral and Microsporidian diseases in deep sea and coastal fin and shell fishes of Bay of Bengal and Andaman waters” (File No: MoES/PAMC/DOM/92/2023). Author Contribution Vasanthan Koothan sample collection, sample processing, conceptualization, methodology development, investigation, data recording, and formal analysis. Ayyaru Gopalakrishnan revised the manuscript with comprehensive guidance and provided support throughout the work. The authors have thoroughly reviewed the manuscript. Acknowledgements Authors would like to acknowledge; The Dean and Director of Centre of Advanced Study in Marine Biology, Annamalai University Tamil Nadu, India for providing facilities and encouragement. 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J Coastal Life Med 3:438–440 Vijayapoopathi S, Ayyaru G, Kuzhanthaivel R, Syed A (2016) Lymphocystis in Indian oil sardine, Sardinella longiceps (Valenciennes, 1847). Asian Pac J Trop Dis 6:611–614. https://doi.org/10.1016/S2222-1808(16)61100-1 Vinothkumar R, Rameshkumar P, Saravanan R, Surya S, Nazar A, Rohit P (2017) Neoplasia in oil sardine from Palk Bay. Mar Fish Inf Serv Tech Ext Ser 231:29–30 Lam SW, van Langevelde K, Suurmeijer AJ, Cleven AH, Bovée JV (2019) Conventional chondrosarcoma with focal clear cell change: a clinicopathological and molecular analysis. Histopathology 75:843–852. https://doi.org/10.1111/his.13921 Depboylu B, Tasan SC, Tataroglu C (2023) Chondrosarcoma: an analysis of clinical characteristics, treatment outcomes, and prognostic factors in a decade-long single center experience. Atl J Med Sci Res 3:116–124. https://doi.org/10.5455/tjmed.2023.06.041 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 02 Feb, 2026 Editor assigned by journal 02 Feb, 2026 Submission checks completed at journal 02 Feb, 2026 First submitted to journal 24 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8685456","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":584466637,"identity":"68a1382f-1f0a-4ff5-87f1-ed5f107014c5","order_by":0,"name":"Vasanthan Koothan","email":"","orcid":"","institution":"Annamalai University","correspondingAuthor":false,"prefix":"","firstName":"Vasanthan","middleName":"","lastName":"Koothan","suffix":""},{"id":584466638,"identity":"5c5baf32-d637-4074-8d75-be8866f049e6","order_by":1,"name":"Ayyaru Gopalakrishnan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIiWNgGAWjYDADPvYGIGlgQYIWNp4DIC0SpGiRSABRRGjhb88x/Pil4o48m+Tzqxt+FEgARboT8GqROPPGWFrmzDPDNumcsps9QIdJnDm7Ab81N3IMpCXbDjMCtaTd4AFqMZDIxa9F/kaO8W+gFvs2yTNpN/8Qo8XgRo6Z5Me2w4ltEuzHbhNli+GZZ2XWDGeeJbfx5LDdljGQ4CHoF7njyZtv/qi4Y9vPfvzZzTd/bOT423sJeJ8hgYGZh+EAkMFjAOLyEFAO0cL4A6yF/QERqkfBKBgFo2AkAgCNjkmpYbPwlwAAAABJRU5ErkJggg==","orcid":"","institution":"Annamalai University","correspondingAuthor":true,"prefix":"","firstName":"Ayyaru","middleName":"","lastName":"Gopalakrishnan","suffix":""}],"badges":[],"createdAt":"2026-01-24 09:27:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8685456/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8685456/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104398284,"identity":"c15daca2-b376-468a-8fe4-52b1e883875a","added_by":"auto","created_at":"2026-03-11 12:01:17","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":199411,"visible":true,"origin":"","legend":"\u003cp\u003eThe affected specimen Largescale Mullet (\u003cem\u003ePlaniliza macrolepis)\u003c/em\u003e; The close-up view affected portion shows the prominent tumorous outgrowth.\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8685456/v1/905a0855c016b528ccb3f4a4.jpg"},{"id":104406591,"identity":"4de4cbea-afe1-4539-942f-feb83cae6935","added_by":"auto","created_at":"2026-03-11 12:28:54","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":131911,"visible":true,"origin":"","legend":"\u003cp\u003eHistological features of chondrosarcoma in the largescale mullet \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e. (A-B) Haematoxylin and eosin-stained sections showing increased cellularity of neoplastic chondrocytes embedded within a chondroid matrix, with nuclear pleomorphism, hyperchromasia, and frequent binucleation.\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8685456/v1/447ed53f08055386a5170242.jpg"},{"id":103576093,"identity":"ce506116-a797-4be9-b171-9f7a3b629827","added_by":"auto","created_at":"2026-02-27 09:12:37","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":474244,"visible":true,"origin":"","legend":"\u003cp\u003eHistological features of chondrosarcoma tissue with special stain\u003cstrong\u003e \u003c/strong\u003e(C-D) Toluidine Blue-stained sections demonstrating metachromasia of the extracellular matrix, confirming chondroid differentiation. (E-F) Alcian Blue (pH 2.5) stained sections showing strong positivity of the tumour matrix, indicating abundant acidic mucopolysaccharides and sulfated glycosaminoglycans. Scale bars: A, C = 50 μm; B, D = 20 μm.\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8685456/v1/080bf21278e8c07cabc23f44.jpg"},{"id":103576095,"identity":"382cdd74-909b-4391-aeda-11b64b252471","added_by":"auto","created_at":"2026-02-27 09:12:37","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":420953,"visible":true,"origin":"","legend":"\u003cp\u003eTransmission electron microscopy shows the viral particles (arrow) present in tumour affected tissue of \u003cem\u003ePlaniliza macrolepis \u003c/em\u003e(A)\u003cem\u003e.\u003c/em\u003e The close-up view of “A” shows the virus-like particles were enveloped with protein capsid (arrows) and nucleocapsid, protein envelope and electron dense nucleocapsid (B). Scale bars = 500nm\u003c/p\u003e","description":"","filename":"Picture4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8685456/v1/fc526815fa3ab8deab56094c.jpg"},{"id":104412001,"identity":"fe95ab00-fb27-4c73-813b-d9c354654824","added_by":"auto","created_at":"2026-03-11 12:58:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1697444,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8685456/v1/561aa3f4-f248-428f-9e5b-ebe2e54fc064.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Suggestive Case of Viral-Induced Chondrosarcoma (Chondrogenic Neoplasia) in Largescale Mullet, Planiliza macrolepis (Smith, 1846) from the Pondicherry, Southeast Coast of India","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe largescale mullet (\u003cem\u003ePlaniliza macrolepis\u003c/em\u003e) is a member of the Mugilidae family and is commonly found in coastal and estuarine waters across the Indo-Pacific region (Whitfield et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). This fish species is distinguished by its streamlined, elongated body and conspicuously large scales. Individuals can grow up to approximately 50 cm (20 inches) in length. Its silvery-gray body, which fades to a lighter tone on the underside, serves as effective camouflage within its aquatic habitat. Mature fish are predominantly herbivorous, consuming algae and organic detritus, and typically form shoals an adaptive behavior that enhances protection against predators. \u003cem\u003eP. macrolepis\u003c/em\u003e is ecologically important for nutrient cycling in coastal ecosystems and economically valuable as a reliable food source. It supports both artisanal and commercial fisheries, providing sustenance and income for coastal communities across the Indo-Pacific region.\u003c/p\u003e \u003cp\u003eTumor development, or neoplasia, is well-documented in fish and follows classification patterns similar to those in higher vertebrates (Knusel et al. 2007; Hochwartner et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). In India, an increasing number of neoplastic conditions have been documented in marine fishes, and these lesions are widely regarded as important biological indicators of environmental stressors, including pollution and the emergence of infectious diseases (Chavan et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Gopalakrishnan et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Sinduja et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Sinduja et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Vijayakumar et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Singaravel et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Vijayakumar et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Singaravel et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003ea-e; Vijayapoopathi et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Vinothkumar et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Singaravel et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Singaravel et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Mariasingrayan et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Singaravel and Gopalakrishnan \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Mariasingarayan et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Koothan et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2026a\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003eb\u003c/span\u003e). The occurrence of tumours in wild fish populations has been linked to multiple etiological factors, such as exposure to chemical pollutants, genetic susceptibility, prolonged inflammatory processes, and infectious agents, with particular emphasis on oncogenic viruses (Zhou et al. 2010; Coffee et al. 2013; Li 2014; Vijayakumar et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Duis and Coors 2016; Carolin et al. 2017; Singaravel et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Hader et al. 2020; Baines et al. 2021; Singaravel and Gopalakrishnan \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eChondrosarcoma is a malignant cartilage-forming neoplasm characterized by the production of chondroid matrix by neoplastic chondrocytes and represents one of the most common primary cartilaginous tumours (Lokuhetty et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Weinschenk et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Histologically, it is defined by increased cellularity, nuclear atypia, hyperchromasia, frequent binucleation, and an infiltrative growth pattern within hyaline or myxoid cartilage. Chondrosarcomas exhibit considerable morphological and biological heterogeneity and are commonly classified based on histological grade, which correlates with tumour aggressiveness and prognosis. While extensively studied in terrestrial vertebrates, particularly in humans and domestic animals, chondrosarcoma is infrequently reported in fishes, and its pathogenesis, biological behaviour, and etiological factors in aquatic species remain poorly understood.\u003c/p\u003e \u003cp\u003eChondrogenic tumours have been previously reported in fishes (Mesbah et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Sirri et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2009\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Among these, chondrosarcoma represents a malignant and more specific chondrogenic neoplasm and was first identified in fish in species such as the paddlefish \u003cem\u003ePolyodon spathula\u003c/em\u003e (Bean-Knudsen et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1987\u003c/span\u003e). However, documentation of chondrogenic -chondrosarcoma in other fish species remains extremely limited. The present study reports the first documented case of chondrogenic-chondrosarcoma in the largescale mullet \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e, thereby expanding the known host range of this rare malignant chondrogenic tumour in teleost fishes.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSample Collection\u003c/h2\u003e \u003cp\u003eDuring a routine biological sample survey conducted under a Ministry of Earth Sciences, Government of India-sanctioned project under Deep Ocean Mission (DOM). an adult female largescale mullet (\u003cem\u003ePlaniliza macrolepis\u003c/em\u003e) exhibiting signs of external tumour development was collected in August 2025. The specimen was procured from the Pondicherry fish market, located along the southeast coast of India. The fish weighed 760 g and measured 44 cm in total length, and showed conspicuous abnormal growths near the caudal peduncle. Owing to this unusual presentation, the specimen was selected for detailed laboratory analysis.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eGross Pathological Examination\u003c/h3\u003e\n\u003cp\u003eA macroscopic assessment was performed to record the tumor's size, shape, surface characteristics, coloration, and consistency. The mass was carefully excised and its dimensions (length, width, and height) were recorded. High-quality photographs were taken under controlled lighting to document external features and any notable variations in appearance, such as discoloration or texture.\u003c/p\u003e\n\u003ch3\u003eHistological Analysis\u003c/h3\u003e\n\u003cp\u003eThe tumour tissue samples were excised and fixed for 24 h in 10% neutral buffered formalin (NBF) solution, followed by several washes in tap water prior to dehydration through a graded alcohol series, cleared in xylene, and embedded in paraffin wax. Thin sections (5 \u0026micro;m) were prepared using a rotary microtome (LEICA RM2125 RTS) and stained with haematoxylin and eosin (Coolidge and Howard 1979). Additional sections were stained with Alcian Blue (pH 2.5) and Toluidine Blue. The stained tissue sections were examined under a light microscope (LEICA DM 2500 LED).\u003c/p\u003e\n\u003ch3\u003eTransmission Electron Microscopy (TEM)\u003c/h3\u003e\n\u003cp\u003eTumor tissue was aseptically excised and fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4) for 24 hours, followed by post-fixation in 1% osmium tetroxide for 3 hours. After dehydration through an ascending ethanol series, tissues were embedded in Epon resin. Semi-thin sections were stained with toludine blue, while ultra-thin sections were stained with uranyl acetate and lead citrate. Samples were observed under a Philips Tecnai T12 Spirit TEM operating at 80 kV to analyze ultrastructural features.\u003c/p\u003e"},{"header":"RESULT","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eGross Pathology\u003c/h2\u003e \u003cp\u003eExternal examination of the affected \u003cem\u003eP. macrolepis\u003c/em\u003e specimen revealed a prominent mass located near anterior to the caudal fin, extending across both the dorsal and ventral surfaces of the tail region. The tumor measured approximately 3.0 \u0026times; 3.1 \u0026times; 3.2 cm and exhibited a firm, rigid consistency. It presented as an irregularly spherical mass with a distinct pinkish-white coloration, suggestive of potential underlying tissue changes or vascular alterations (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eHistopathology\u003c/h3\u003e\n\u003cp\u003eHistological examination of haematoxylin and eosin-stained sections revealed a neoplastic lesion composed of abundant chondroid matrix with numerous chondrocyte-like cells embedded within well-defined lacunae (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA\u0026amp;B). The tumour showed increased cellularity with irregular clustering of cells. Neoplastic chondrocytes exhibited moderate to marked nuclear pleomorphism, hyperchromasia, and frequent binucleation; occasional multinucleated cells were also observed, while mitotic figures were rare. Toluidine Blue-stained sections demonstrated pronounced metachromasia of the extracellular matrix, confirming the presence of a chondroid matrix (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003eA\u0026amp;B). Alcian Blue (pH 2.5) staining showed strong and diffuse positivity of the tumour matrix, indicating abundant acidic mucopolysaccharides and sulfated glycosaminoglycans characteristic of cartilaginous tissue (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003eC\u0026amp;D).\u003c/p\u003e\n\u003ch3\u003eTransmission Electron Microscopy\u003c/h3\u003e\n\u003cp\u003eUltrastructural analysis of tumor tissue revealed numerous virus-like particles (VLPs) within the cytoplasm of affected cells. These particles were spherical to polyhedral in shape, ranging from 200 to 250 nm in diameter. Each VLP exhibited a distinct nucleocapsid enclosed by an electron-dense protein capsid. The viral particles were distributed throughout the cytoplasm, indicating potential viral involvement in tumor pathogenesis (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eNeoplasia has been documented across a broad phylogenetic spectrum of fishes and virtually all organ systems, reflecting both the evolutionary antiquity of tumorigenesis and the susceptibility of aquatic vertebrates to diverse carcinogenic influences (Wellings \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1969\u003c/span\u003e; Roberts \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). The etiology of fish tumors is widely regarded as multifactorial, involving complex interactions between environmental contaminants, genetic predisposition, age, sex, chronic tissue irritation, and infectious agents, particularly oncogenic viruses (Vielkind \u0026amp; Vielkind \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1982\u003c/span\u003e; Anders \u0026amp; Yoshimizu \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Okihiro et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). In recent decades, the increasing frequency of tumor reports in wild marine fishes from Indian coastal waters has highlighted neoplasia as a valuable biological indicator of ecosystem health and environmental stress (Chavan et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Gopalakrishnan et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Singaravel et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003ea\u0026ndash;e; Vinothkumar et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Mariasingrayan et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe present study documents a rare chondrogenic malignancy in the largescale mullet \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e, a widely distributed and ecologically important mugilid species (Whitfield et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Grossly, the tumor presented as a firm, irregular, pinkish-white mass located near the caudal peduncle, a morphology comparable to previously described chondrogenic neoplasms in fishes, including cranial chondrosarcoma in paddlefish (\u003cem\u003ePolyodon spathula\u003c/em\u003e) (Bean-Knudsen et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1987\u003c/span\u003e) and chondromas in grass carp and neon tetra (Sirri et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2009\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Mesbah et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The size, rigidity, and invasive appearance of the lesion in the present case are consistent with malignant behavior rather than a benign cartilaginous proliferation.\u003c/p\u003e \u003cp\u003eHistopathological evaluation provided definitive evidence supporting a diagnosis of chondrosarcoma. The tumor was characterized by abundant chondroid matrix containing densely packed neoplastic chondrocytes within lacunae, marked hypercellularity, nuclear pleomorphism, hyperchromasia, and frequent binucleation. These features are in agreement with the diagnostic criteria for chondrosarcoma described in the WHO Classification of Tumours of Soft Tissue and Bone (Lokuhetty et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) and with clinicopathological descriptions in higher vertebrates (Weinschenk et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Lam et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Although mitotic figures were infrequent, this finding does not preclude malignancy, as low mitotic activity has also been reported in conventional chondrosarcomas with infiltrative growth and aggressive potential (Depboylu et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eChondrogenic tumors are exceedingly uncommon in teleost fishes, and most reported cases are benign chondromas rather than malignant chondrosarcomas (Sirri et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2009\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Mesbah et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). To date, chondrosarcoma has been documented only sporadically in fishes, notably in paddlefish (Bean-Knudsen et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1987\u003c/span\u003e). Therefore, the present report represents the first confirmed case of chondrosarcoma in \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e and expands both the taxonomic and anatomical spectrum of malignant cartilaginous tumors in teleosts.\u003c/p\u003e \u003cp\u003eMugilid fishes are known to develop a variety of neoplasms, including squamous cell carcinoma (Jithendran et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), myxoinflammatory fibroblastic sarcoma, leiomyoma (Singaravel et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003eb), and cutaneous fibroma (Mariasingrayan et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). However, cartilaginous malignancies have not previously been reported in this group. The present finding therefore underscores the neoplastic diversity observed in mullets and suggests that mugilids may be more susceptible to mesenchymal tumors than previously recognized.\u003c/p\u003e \u003cp\u003eA particularly noteworthy aspect of this study is the ultrastructural detection of virus-like particles (VLPs) within the cytoplasm of neoplastic cells. Viral involvement in fish tumorigenesis has been well documented, especially in epidermal papillomas, lymphocystis, and chromatophoromas (Anders \u0026amp; Yoshimizu \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Okihiro et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Vijayapoopathi et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The presence of VLPs in the present case raises the possibility of a viral role in the initiation or progression of chondrosarcoma in \u003cem\u003eP. macrolepis\u003c/em\u003e. While causality cannot be established based solely on ultrastructural observations, similar associations between viral particles and neoplastic tissues have been reported in other fish tumors, supporting a viral oncogenesis hypothesis (Anders \u0026amp; Yoshimizu \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Roberts \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe increasing number of tumor reports from Indian coastal waters, including melanophoromas, chromatophoromas, fibrosarcomas, odontomas, and various epithelial and mesenchymal neoplasms (Singaravel et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2015\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2016\u003c/span\u003ed, 2017; Vijayakumar et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2014\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Koothan et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2026a\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003eb\u003c/span\u003e), suggests that environmental stressors such as pollution, habitat degradation, and pathogen emergence may play an important role in tumor development. Given the ecological and commercial significance of \u003cem\u003eP. macrolepis\u003c/em\u003e, the occurrence of a malignant tumor in a wild individual is of concern and warrants further epidemiological and molecular investigations.\u003c/p\u003e \u003cp\u003eIn conclusion, this study provides the first evidence of chondrosarcoma in the largescale mullet \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e and adds to the limited global literature on malignant chondrogenic tumors in fishes. The combined gross, histopathological, histochemical, and ultrastructural findings strongly support the diagnosis and suggest a possible viral contribution to tumor pathogenesis. Continued surveillance of neoplastic diseases in wild fish populations, coupled with advanced molecular diagnostics, is essential for understanding tumor etiology, assessing environmental health, and safeguarding fishery resources.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of Interest\u003c/h2\u003e \u003cp\u003eThe authors declare that there is no conflict of interest related to the publication of this\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eEthics Statement\u003c/h2\u003e \u003cp\u003eThe manuscript does not require ethical approval. According to the guidelines framed by the Government of India for experiments on fish (CPCSEA), ethical approval is required only for experimental studies and wild fishes, not for research involving dead food fish obtained from such landing sites.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThe authors gratefully acknowledge the Ministry of Earth Sciences, Government of India, for the financial support provided under the Deep Ocean Mission (DOM) for the project entitled \u0026ldquo;Prevalence of emerging Viral and Microsporidian diseases in deep sea and coastal fin and shell fishes of Bay of Bengal and Andaman waters\u0026rdquo; (File No: MoES/PAMC/DOM/92/2023).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eVasanthan Koothan sample collection, sample processing, conceptualization, methodology development, investigation, data recording, and formal analysis. Ayyaru Gopalakrishnan revised the manuscript with comprehensive guidance and provided support throughout the work. The authors have thoroughly reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eAuthors would like to acknowledge; The Dean and Director of Centre of Advanced Study in Marine Biology, Annamalai University Tamil Nadu, India for providing facilities and encouragement. We also acknowledge the fishing communities at sampling localities for their help during fish collection and the supply of fish samples.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWhitfield AK, Panfili J, Durand JD (2012) A global review of the cosmopolitan flathead mullet \u003cem\u003eMugil cephalus\u003c/em\u003e Linnaeus 1758 (Teleostei: Mugilidae), with emphasis on the biology, genetics, ecology and fisheries aspects of this apparent species complex. 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Atl J Med Sci Res 3:116\u0026ndash;124. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5455/tjmed.2023.06.041\u003c/span\u003e\u003cspan address=\"10.5455/tjmed.2023.06.041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"veterinary-research-communications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"verc","sideBox":"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)","snPcode":"11259","submissionUrl":"https://submission.nature.com/new-submission/11259/3","title":"Veterinary Research Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Chondrosarcoma, Chondrogenic neoplasia, Planiliza macrolepis, Fish neoplasia","lastPublishedDoi":"10.21203/rs.3.rs-8685456/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8685456/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eNeoplasia in wild fish populations is increasingly recognized as an important indicator of environmental stress and ecosystem health. The present study reports the first documented case of suggestive chondrosarcoma (chondrogenic neoplasia) in the largescale mullet \u003cem\u003ePlaniliza macrolepis\u003c/em\u003e (Smith, 1846) from the southeast coast of India. An adult female specimen exhibiting a conspicuous external mass near the caudal peduncle was collected from the Pondicherry fish landing center during a routine survey. Gross examination revealed a firm, irregular, pinkish-white tumorous growth measuring approximately 3.0 \u0026times; 3.1 \u0026times; 3.2 cm. Histopathological analysis demonstrated a malignant cartilaginous neoplasm characterized by abundant chondroid matrix, marked hypercellularity, nuclear pleomorphism, hyperchromasia, frequent binucleation, and chondrocyte-like cells within well-defined lacunae. Histochemical staining with Alcian Blue (pH 2.5) and Toluidine Blue confirmed the cartilaginous nature of the extracellular matrix. Ultrastructural examination using transmission electron microscopy revealed the presence of virus-like particles within the cytoplasm of neoplastic cells, suggesting a possible viral involvement in tumor development. Chondrosarcoma is exceedingly rare in teleost fishes, and this finding expands the known host range of malignant chondrogenic tumors in aquatic vertebrates. The present case highlights the need for continued surveillance of neoplastic diseases in marine fishes and underscores the potential role of infectious agents and environmental stressors in tumorigenesis within coastal ecosystems.\u003c/p\u003e","manuscriptTitle":"Suggestive Case of Viral-Induced Chondrosarcoma (Chondrogenic Neoplasia) in Largescale Mullet, Planiliza macrolepis (Smith, 1846) from the Pondicherry, Southeast Coast of India","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-27 09:12:00","doi":"10.21203/rs.3.rs-8685456/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-02T15:30:24+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-02T13:00:08+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-02T12:52:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Veterinary Research Communications","date":"2026-01-24T09:06:35+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"veterinary-research-communications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"verc","sideBox":"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)","snPcode":"11259","submissionUrl":"https://submission.nature.com/new-submission/11259/3","title":"Veterinary Research Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"579c012e-62ff-4d2f-8619-6c9faf30eb70","owner":[],"postedDate":"February 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-27T09:12:02+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-27 09:12:00","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8685456","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8685456","identity":"rs-8685456","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}