Histopathological diagnosis of invasive pulmonary candidiasis mimicking bronchogenic carcinoma in an immunocompetent adult: a case report

Histopathological diagnosis of invasive pulmonary candidiasis mimicking bronchogenic carcinoma in an immunocompetent adult: a case report | 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 Histopathological diagnosis of invasive pulmonary candidiasis mimicking bronchogenic carcinoma in an immunocompetent adult: a case report Okello Malcom Mark, Male Mutumba, Kalungi Sam, Kirabo Mark Iga, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9052757/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background. Invasive pulmonary candidiasis is an uncommon and frequently disputed diagnosis because Candida species commonly colonize the respiratory tract without causing tissue invasion. Definitive diagnosis, therefore, relies on histopathological demonstration of fungal invasion with concurrent inflammation. We report a case of invasive pulmonary candidiasis presenting as an endobronchial mass mimicking bronchogenic carcinoma in an adult male without known immunosuppression. Case presentation. A 49-year-old Ugandan male presented with a two-month history of dry cough, chest pain, progressive worsening dyspnea, intermittent fever, and non-bloody diarrhea. The fever was moderate grade and intermittent without rigors or night sweats. He developed septic shock and hypoxemic respiratory failure requiring intensive care unit admission. Radiological evaluation demonstrated left lower lobe consolidation with minimal parapneumonic effusion. Bronchoscopy revealed a narrowed bronchial lumen due to an endobronchial mass, raising suspicion for bronchogenic carcinoma. Histopathological examination of bronchoscopic biopsy specimens demonstrated non-branching pseudohyphae consistent with Candida species, confirming invasive pulmonary candidiasis. Blood, sputum, urine, and pleural fluid cultures were negative. The patient improved clinically following antifungal therapy and was discharged home on oral antifungal therapy. Conclusion. This case highlights the diagnostic challenge of invasive pulmonary candidiasis and underscores the indispensable role of histopathology in distinguishing true tissue invasion from colonization. In patients with persistent pneumonia and endobronchial lesions, invasive fungal infection should be considered even in the absence of classical immunosuppression. Pathology Infectious Diseases General Microbiology Invasive pulmonary candidiasis Histopathology Candida species Endobronchial mass Pneumonia Case report Background Pulmonary involvement by Candida species remains a controversial entity because Candida commonly colonizes the upper and lower respiratory tract, particularly in hospitalized patients( 1 , 2 ). Consequently, respiratory cultures alone are insufficient for diagnosis( 3 ). True invasive pulmonary candidiasis is rare and requires histopathological evidence of fungal invasion into lung tissue for confirmation( 3 ). Failure to recognize this entity may lead to delayed or inappropriate management, especially when radiologic or bronchoscopic findings mimic malignancy or bacterial pneumonia( 4 ). Case presentation A 49-year-old male farmer from Kikuube district, western Uganda, who had only for four days been a casual labourer working with the China Petroleum Pipeline project in Hoima District, western Uganda, presented on 22 January 2026 with dry cough, chest pain of two months duration, progressive dyspnea for four days, fever, and diarrhea. The fever was moderate grade and intermittent without chills, rigors, or night sweats. He had been unwell for approximately two months before presentation and was referred from a peripheral health facility. He had no known history of diabetes mellitus, hypertension, chronic lung disease, malignancy, or immunosuppressive conditions. There was no history of active smoking. There was no significant weight loss. He had recently engaged in manual labour involving digging and filling soil bags during pipeline construction. Clinical examination. On admission, he was anxious and acutely ill-appearing. Vital signs revealed hypotension (blood pressure 97/56 mmHg), tachypnea (respiratory rate 29 breaths/min), and severe hypoxemia with oxygen saturation of 70% on room air, improving to 90% on 10 L via non-rebreather mask. Pulse rate was 91 beats/min, temperature 36.1°C, and Glasgow Coma Scale score was 15/15. Use of accessory muscles of respiration was noted. Cardiovascular and abdominal examinations were unremarkable. A preliminary diagnosis of sepsis with severe pneumonia, acute respiratory distress, metabolic acidosis, and possible pulmonary embolism was made. Investigations. Baseline laboratory investigations included complete blood count, liver and renal function tests, venous blood gas analysis, blood glucose, procalcitonin, blood cultures, urine culture, and HIV testing. Blood, urine, and sputum cultures showed no growth. HIV testing was negative. Electrocardiography and echocardiography were normal. CTPA demonstrated left lower lobe consolidation consistent with pneumonia with minimal parapneumonic effusion, and no evidence of pulmonary embolism. Due to persistent symptoms and radiologic findings, bronchoscopy was performed. This revealed narrowing of the bronchial lumen by an endobronchial mass, raising suspicion for bronchogenic carcinoma. Bronchoscopic biopsy specimens were obtained for histological analysis. Histopathology diagnosis. Microscopic examination demonstrated combined non-branching pseudohyphae and budding yeast infiltrating tissue with marked tissue necrosis and inflammation, consistent with invasive Candida species. These findings established a diagnosis of invasive pulmonary candidiasis, rather than mere colonization. Differential diagnosis The main differential diagnoses considered included: Bronchogenic carcinoma Bacterial pneumonia with endobronchial obstruction Invasive pulmonary aspergillosis Pulmonary mucormycosis Histopathological morphology excluded filamentous fungi such as Aspergillus (septate, acute-angle branching hyphae) and mucormycosis (broad, aseptate hyphae), supporting Candida infection. Treatment and outcome The patient required intensive care management, including high-flow oxygen, intravenous fluids (crystalloids), vasopressor support with noradrenaline, broad-spectrum antibiotics, and electrolyte correction. Following histopathological diagnosis, antifungal therapy was initiated. He was initiated on oral itraconazole 200 mg once daily in addition to antibiotics. He showed significant clinical improvement, was weaned off oxygen, and was no longer in respiratory distress by day 5 after initiating Itracozole, which was day 10 of admission. He was discharged to continue taking oral Itraconazole at home after 15 days in the hospital. Discussion Invasive pulmonary candidiasis (IPC) is rare and often over- or misdiagnosed when based solely on respiratory cultures ( 4 ). Although Candida species frequently colonize healthy people's mucosal and dermal surfaces, invasion can happen when immune or mechanical defences are compromised ( 5 ). The incidence of invasive pulmonary candidiasis is rising in both immunosuppressed and immunocompetent patients ( 1 , 6 ). This case illustrates a classic diagnostic pitfall: an endobronchial lesion mimicking malignancy, forming a nodule within the bronchus ( 7 ), with negative cultures but definitive histopathological evidence of fungal invasion. IPC may induce sepsis or ultimately septic shock, both indistinguishable from bacterial infection ( 8 ). Fungal cultures may be negative even in proven invasive disease; histopathology remains the prerequisite for definitive diagnosis( 3 ). The absence of traditional immunosuppressive risk factors in this patient further underscores the importance of tissue diagnosis ( 3 ). At admission, the laboratory tests indicated severe systemic inflammation and sepsis. The full blood count demonstrated marked leucocytosis with neutrophilia (total white blood cell = 20.02 ×10⁹/L; absolute neutrophils = 13.7 ×10⁹/L), accompanied by absolute monocytosis and relative eosinopenia. Acute phase reactants were significantly elevated, with procalcitonin peaking at 25.54 ng/mL, and CRP was markedly raised (> 270 mg/L), consistent with high-risk severe sepsis or septic shock as shown in some studies ( 9 , 10 ). Despite this intense inflammatory response, initial microbiological investigations were negative. HIV serology was non-reactive, malaria testing was negative, and both aerobic and anaerobic blood cultures subsequently showed no growth after five days of incubation, arguing against bacteraemia as a cause of sepsis, which is consistent with culture-negative invasive pulmonary candidiasis ( 2 ). Renal function was preserved, while electrolyte abnormalities (hypocalcaemia and hypomagnesemia) were noted, consistent with critical illness–related metabolic derangements. Cardiac biomarkers (CK-MB and troponin) were transiently elevated, but without corroborative ECG evidence of acute coronary pathology. Microbiological evaluation of blood specimens did not yield a pathogen and this was consistent with study in Eastern Uganda that showed culture negative sepsis in up to 47% of patients( 11 ). Respiratory specimen such as sputum microscopy and culture was negative for bacteria, fungi, and acid-fast bacilli, with Bartlett’s score indicating an adequate sample but no identifiable infectious agent. Urine analysis and culture were unremarkable. These findings further deepened the diagnostic dilemma of culture-negative sepsis in a patient with progressive pulmonary disease ( 3 , 12 ) Histopathology remains the gold standard for diagnosis of IPC, particularly in resource-limited settings where advanced fungal diagnostics may be unavailable( 3 , 13 ). This case reinforces that IPC should be considered in patients with persistent pneumonia and atypical bronchoscopic findings, even when cultures are negative. Conclusion Histopathological demonstration of tissue-invasive Candida is essential for the diagnosis of invasive pulmonary candidiasis. This case emphasizes that invasive pulmonary candidiasis can masquerade as bronchogenic carcinoma and occur in patients without overt immunosuppression. Early biopsy and pathological evaluation are critical to ensure timely, accurate diagnosis and appropriate antifungal therapy. Abbreviations CK-MB Creatinine kinase-MB CRP C-reactive protein CTPA Computed tomography pulmonary angiography ECG Electrocardiogram HIV Human immunodeficiency virus IPC Invasive pulmonary candidiasis Declarations Ethics approval and consent to participate Not applicable. Consent for publication Written informed consent was obtained from the patient for publication of this case report and accompanying images. Competing interests The authors declare no competing interests. Funding None. Availability of data and materials The data generated or analyzed during this study are included in this published article. Patient identifiers were omitted. References KAKDE Y, SHAH D, ACHARYA S, SHUKLA S (2023) KUMAR S. Pulmonary Candidiasis in an Immunocompetent Patient. J Clin Diagn Res. ;17(4) Clancy CJ, Nguyen MH (2018) Diagnosing Invasive Candidiasis. J Clin Microbiol 56(5). 10.1128/jcm.01909-17 Guarner J, Brandt ME (2011) Histopathologic Diagnosis of Fungal Infections in the 21st Century. Clin Microbiol Rev 24(2):247–280 Kullberg BJ, Arendrup MC (2015) Invasive Candidiasis. N Engl J Med 373(15):1445–1456 Epelbaum O, Marinelli T, Haydour Q, Pennington KM, Evans SE, Carmona EM et al (2025) Treatment of Invasive Pulmonary Aspergillosis and Preventive and Empirical Therapy for Invasive Candidiasis in Adult Pulmonary and Critical Care Patients: An Official American Thoracic Society Clinical Practice Guideline. Am J Respir Crit Care Med 211(1):34–53 Webb BJ, Ferraro JP, Rea S, Kaufusi S, Goodman BE, Spalding J (2018) Epidemiology and Clinical Features of Invasive Fungal Infection in a US Health Care Network. Open Forum Infect Dis. ;5(8) Althoff Souza C, Müller NL, Marchiori E, Escuissato DL, Franquet T (2006) Pulmonary Invasive Aspergillosis and Candidiasis in Immunocompromised Patients: A Comparative Study of the High-Resolution CT Findings. J Thorac Imaging. ;21(3) Delaloye J, Calandra T (2014) Invasive candidiasis as a cause of sepsis in the critically ill patient. Virulence 5(1):161–169 Saxena J, Das S, Kumar A, Sharma A, Sharma L, Kaushik S et al (2024) Biomarkers in sepsis. Clin Chim Acta 562:119891 Kadim MM, AL-Dahmoshi HOM, AL-Khikani FHO (2024) Sepsis Biomarkers: Current Information and Future Visions. Microbes Infect Dis 5(1):201–210 Kara N, Peris A, Abonga C, Muyinda A, Muhumuza J, Akaba K et al (2025) Prevalence, bacterial profile, antimicrobial resistance pattern, and predictors of blood culture positive sepsis among adults admitted at Jinja Regional Referral Hospital in Uganda. Front Trop Dis. ;Volume 6–2025 Sekhawat V (2024) A histopathological approach to diagnosis and classification of invasive fungal infections. Diagn Histopathology 30(10):554–563 Okoye CA, Nweze E, Ibe C (2022) Invasive candidiasis in Africa, what is the current picture? Pathogens Disease. ;80(1) Additional Declarations The authors declare no competing interests. Supplementary Files Supplements.docx Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-9052757","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":602039168,"identity":"d3415b1e-7e7c-4b14-86c8-bf87a5b1a930","order_by":0,"name":"Okello Malcom 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report\u003c/p\u003e","fulltext":[{"header":"Background","content":"\u003cp\u003ePulmonary involvement by Candida species remains a controversial entity because Candida commonly colonizes the upper and lower respiratory tract, particularly in hospitalized patients(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Consequently, respiratory cultures alone are insufficient for diagnosis(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). True invasive pulmonary candidiasis is rare and requires histopathological evidence of fungal invasion into lung tissue for confirmation(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Failure to recognize this entity may lead to delayed or inappropriate management, especially when radiologic or bronchoscopic findings mimic malignancy or bacterial pneumonia(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e "},{"header":"Case presentation","content":"\u003cp\u003eA 49-year-old male farmer from Kikuube district, western Uganda, who had only for four days been a casual labourer working with the China Petroleum Pipeline project in Hoima District, western Uganda, presented on 22 January 2026 with dry cough, chest pain of two months duration, progressive dyspnea for four days, fever, and diarrhea. The fever was moderate grade and intermittent without chills, rigors, or night sweats. He had been unwell for approximately two months before presentation and was referred from a peripheral health facility.\u003c/p\u003e \u003cp\u003eHe had no known history of diabetes mellitus, hypertension, chronic lung disease, malignancy, or immunosuppressive conditions. There was no history of active smoking. There was no significant weight loss. He had recently engaged in manual labour involving digging and filling soil bags during pipeline construction.\u003c/p\u003e \u003cp\u003e \u003cb\u003eClinical examination.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eOn admission, he was anxious and acutely ill-appearing. Vital signs revealed hypotension (blood pressure 97/56 mmHg), tachypnea (respiratory rate 29 breaths/min), and severe hypoxemia with oxygen saturation of 70% on room air, improving to 90% on 10 L via non-rebreather mask. Pulse rate was 91 beats/min, temperature 36.1\u0026deg;C, and Glasgow Coma Scale score was 15/15. Use of accessory muscles of respiration was noted. Cardiovascular and abdominal examinations were unremarkable.\u003c/p\u003e \u003cp\u003eA preliminary diagnosis of sepsis with severe pneumonia, acute respiratory distress, metabolic acidosis, and possible pulmonary embolism was made.\u003c/p\u003e \u003cp\u003e \u003cb\u003eInvestigations.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eBaseline laboratory investigations included complete blood count, liver and renal function tests, venous blood gas analysis, blood glucose, procalcitonin, blood cultures, urine culture, and HIV testing. Blood, urine, and sputum cultures showed no growth. HIV testing was negative.\u003c/p\u003e \u003cp\u003eElectrocardiography and echocardiography were normal. CTPA demonstrated left lower lobe consolidation consistent with pneumonia with minimal parapneumonic effusion, and no evidence of pulmonary embolism.\u003c/p\u003e \u003cp\u003eDue to persistent symptoms and radiologic findings, bronchoscopy was performed. This revealed narrowing of the bronchial lumen by an endobronchial mass, raising suspicion for bronchogenic carcinoma. Bronchoscopic biopsy specimens were obtained for histological analysis.\u003c/p\u003e \u003cp\u003e \u003cb\u003eHistopathology diagnosis.\u003c/b\u003e \u003c/p\u003e \u003cp\u003eMicroscopic examination demonstrated combined non-branching pseudohyphae and budding yeast infiltrating tissue with marked tissue necrosis and inflammation, consistent with invasive Candida species. These findings established a diagnosis of invasive pulmonary candidiasis, rather than mere colonization.\u003c/p\u003e\n\u003ch3\u003eDifferential diagnosis\u003c/h3\u003e\n\u003cp\u003eThe main differential diagnoses considered included:\u003c/p\u003e \u003cp\u003eBronchogenic carcinoma\u003c/p\u003e \u003cp\u003eBacterial pneumonia with endobronchial obstruction\u003c/p\u003e \u003cp\u003eInvasive pulmonary aspergillosis\u003c/p\u003e \u003cp\u003ePulmonary mucormycosis\u003c/p\u003e \u003cp\u003eHistopathological morphology excluded filamentous fungi such as Aspergillus (septate, acute-angle branching hyphae) and mucormycosis (broad, aseptate hyphae), supporting Candida infection.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eTreatment and outcome\u003c/h2\u003e \u003cp\u003eThe patient required intensive care management, including high-flow oxygen, intravenous fluids (crystalloids), vasopressor support with noradrenaline, broad-spectrum antibiotics, and electrolyte correction. Following histopathological diagnosis, antifungal therapy was initiated. He was initiated on oral itraconazole 200 mg once daily in addition to antibiotics.\u003c/p\u003e \u003cp\u003eHe showed significant clinical improvement, was weaned off oxygen, and was no longer in respiratory distress by day 5 after initiating Itracozole, which was day 10 of admission. He was discharged to continue taking oral Itraconazole at home after 15 days in the hospital.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eInvasive pulmonary candidiasis (IPC) is rare and often over- or misdiagnosed when based solely on respiratory cultures (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Although Candida species frequently colonize healthy people's mucosal and dermal surfaces, invasion can happen when immune or mechanical defences are compromised (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). The incidence of invasive pulmonary candidiasis is rising in both immunosuppressed and immunocompetent patients (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). This case illustrates a classic diagnostic pitfall: an endobronchial lesion mimicking malignancy, forming a nodule within the bronchus (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e), with negative cultures but definitive histopathological evidence of fungal invasion. IPC may induce sepsis or ultimately septic shock, both indistinguishable from bacterial infection (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). Fungal cultures may be negative even in proven invasive disease; histopathology remains the prerequisite for definitive diagnosis(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). The absence of traditional immunosuppressive risk factors in this patient further underscores the importance of tissue diagnosis (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAt admission, the laboratory tests indicated severe systemic inflammation and sepsis. The full blood count demonstrated marked leucocytosis with neutrophilia (total white blood cell\u0026thinsp;=\u0026thinsp;20.02 \u0026times;10⁹/L; absolute neutrophils\u0026thinsp;=\u0026thinsp;13.7 \u0026times;10⁹/L), accompanied by absolute monocytosis and relative eosinopenia. Acute phase reactants were significantly elevated, with procalcitonin peaking at 25.54 ng/mL, and CRP was markedly raised (\u0026gt;\u0026thinsp;270 mg/L), consistent with high-risk severe sepsis or septic shock as shown in some studies (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDespite this intense inflammatory response, initial microbiological investigations were negative. HIV serology was non-reactive, malaria testing was negative, and both aerobic and anaerobic blood cultures subsequently showed no growth after five days of incubation, arguing against bacteraemia as a cause of sepsis, which is consistent with culture-negative invasive pulmonary candidiasis (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Renal function was preserved, while electrolyte abnormalities (hypocalcaemia and hypomagnesemia) were noted, consistent with critical illness\u0026ndash;related metabolic derangements. Cardiac biomarkers (CK-MB and troponin) were transiently elevated, but without corroborative ECG evidence of acute coronary pathology.\u003c/p\u003e \u003cp\u003eMicrobiological evaluation of blood specimens did not yield a pathogen and this was consistent with study in Eastern Uganda that showed culture negative sepsis in up to 47% of patients(\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Respiratory specimen such as sputum microscopy and culture was negative for bacteria, fungi, and acid-fast bacilli, with Bartlett\u0026rsquo;s score indicating an adequate sample but no identifiable infectious agent. Urine analysis and culture were unremarkable. These findings further deepened the diagnostic dilemma of culture-negative sepsis in a patient with progressive pulmonary disease (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eHistopathology remains the gold standard for diagnosis of IPC, particularly in resource-limited settings where advanced fungal diagnostics may be unavailable(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). This case reinforces that IPC should be considered in patients with persistent pneumonia and atypical bronchoscopic findings, even when cultures are negative.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eHistopathological demonstration of tissue-invasive Candida is essential for the diagnosis of invasive pulmonary candidiasis. This case emphasizes that invasive pulmonary candidiasis can masquerade as bronchogenic carcinoma and occur in patients without overt immunosuppression. Early biopsy and pathological evaluation are critical to ensure timely, accurate diagnosis and appropriate antifungal therapy.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCK-MB\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCreatinine kinase-MB\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCRP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eC-reactive protein\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCTPA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputed tomography pulmonary angiography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eECG\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eElectrocardiogram\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHIV\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHuman immunodeficiency virus\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIPC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eInvasive pulmonary candidiasis\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of this case report and accompanying images.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data generated or analyzed during this study are included in this published article. Patient identifiers were omitted.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKAKDE Y, SHAH D, ACHARYA S, SHUKLA S (2023) KUMAR S. Pulmonary Candidiasis in an Immunocompetent Patient. J Clin Diagn Res. ;17(4)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClancy CJ, Nguyen MH (2018) Diagnosing Invasive Candidiasis. J Clin Microbiol 56(5). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1128/jcm.01909-17\u003c/span\u003e\u003cspan address=\"10.1128/jcm.01909-17\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuarner J, Brandt ME (2011) Histopathologic Diagnosis of Fungal Infections in the 21st Century. Clin Microbiol Rev 24(2):247\u0026ndash;280\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKullberg BJ, Arendrup MC (2015) Invasive Candidiasis. N Engl J Med 373(15):1445\u0026ndash;1456\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEpelbaum O, Marinelli T, Haydour Q, Pennington KM, Evans SE, Carmona EM et al (2025) Treatment of Invasive Pulmonary Aspergillosis and Preventive and Empirical Therapy for Invasive Candidiasis in Adult Pulmonary and Critical Care Patients: An Official American Thoracic Society Clinical Practice Guideline. Am J Respir Crit Care Med 211(1):34\u0026ndash;53\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWebb BJ, Ferraro JP, Rea S, Kaufusi S, Goodman BE, Spalding J (2018) Epidemiology and Clinical Features of Invasive Fungal Infection in a US Health Care Network. Open Forum Infect Dis. ;5(8)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlthoff Souza C, M\u0026uuml;ller NL, Marchiori E, Escuissato DL, Franquet T (2006) Pulmonary Invasive Aspergillosis and Candidiasis in Immunocompromised Patients: A Comparative Study of the High-Resolution CT Findings. J Thorac Imaging. ;21(3)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDelaloye J, Calandra T (2014) Invasive candidiasis as a cause of sepsis in the critically ill patient. Virulence 5(1):161\u0026ndash;169\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaxena J, Das S, Kumar A, Sharma A, Sharma L, Kaushik S et al (2024) Biomarkers in sepsis. Clin Chim Acta 562:119891\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKadim MM, AL-Dahmoshi HOM, AL-Khikani FHO (2024) Sepsis Biomarkers: Current Information and Future Visions. Microbes Infect Dis 5(1):201\u0026ndash;210\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKara N, Peris A, Abonga C, Muyinda A, Muhumuza J, Akaba K et al (2025) Prevalence, bacterial profile, antimicrobial resistance pattern, and predictors of blood culture positive sepsis among adults admitted at Jinja Regional Referral Hospital in Uganda. Front Trop Dis. ;Volume 6\u0026ndash;2025\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSekhawat V (2024) A histopathological approach to diagnosis and classification of invasive fungal infections. Diagn Histopathology 30(10):554\u0026ndash;563\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOkoye CA, Nweze E, Ibe C (2022) Invasive candidiasis in Africa, what is the current picture? Pathogens Disease. ;80(1)\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Invasive pulmonary candidiasis, Histopathology, Candida species, Endobronchial mass, Pneumonia, Case report","lastPublishedDoi":"10.21203/rs.3.rs-9052757/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9052757/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground.\u003c/b\u003e\u003c/p\u003e \u003cp\u003eInvasive pulmonary candidiasis is an uncommon and frequently disputed diagnosis because Candida species commonly colonize the respiratory tract without causing tissue invasion. Definitive diagnosis, therefore, relies on histopathological demonstration of fungal invasion with concurrent inflammation. We report a case of invasive pulmonary candidiasis presenting as an endobronchial mass mimicking bronchogenic carcinoma in an adult male without known immunosuppression.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase presentation.\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA 49-year-old Ugandan male presented with a two-month history of dry cough, chest pain, progressive worsening dyspnea, intermittent fever, and non-bloody diarrhea. The fever was moderate grade and intermittent without rigors or night sweats. He developed septic shock and hypoxemic respiratory failure requiring intensive care unit admission. Radiological evaluation demonstrated left lower lobe consolidation with minimal parapneumonic effusion. Bronchoscopy revealed a narrowed bronchial lumen due to an endobronchial mass, raising suspicion for bronchogenic carcinoma. Histopathological examination of bronchoscopic biopsy specimens demonstrated non-branching pseudohyphae consistent with Candida species, confirming invasive pulmonary candidiasis. Blood, sputum, urine, and pleural fluid cultures were negative. The patient improved clinically following antifungal therapy and was discharged home on oral antifungal therapy.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion.\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThis case highlights the diagnostic challenge of invasive pulmonary candidiasis and underscores the indispensable role of histopathology in distinguishing true tissue invasion from colonization. In patients with persistent pneumonia and endobronchial lesions, invasive fungal infection should be considered even in the absence of classical immunosuppression.\u003c/p\u003e","manuscriptTitle":"Histopathological diagnosis of invasive pulmonary candidiasis mimicking bronchogenic carcinoma in an immunocompetent adult: a case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-09 05:25:58","doi":"10.21203/rs.3.rs-9052757/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"281d2451-c791-4704-8720-75cdd1f83153","owner":[],"postedDate":"March 9th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":64142249,"name":"Pathology"},{"id":64142250,"name":"Infectious Diseases"},{"id":64142251,"name":"General Microbiology"}],"tags":[],"updatedAt":"2026-03-09T05:25:58+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-09 05:25:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9052757","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9052757","identity":"rs-9052757","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}