{"paper_id":"db43c4bc-d2b1-477b-9f45-d1f6625c7ee3","body_text":"Title:\nThe volcano sign and mucus outflow by colonoscopy - Low grade appendiceal mucinous neoplasm\nAuthors:\nYuko Tasato, Yoshiki Chinen, Kyoko Arakaki, Mayumi Shiroma, Masaru Miyazato, Noriya Nakachi, Ryosaku\nTomiyama, Akira Hokama\nDOI: 10.17235/reed.2024.10841/2024\nLink: PubMed (Epub ahead of print)\nPlease cite this article as:\nTasato Yuko, Chinen Yoshiki , Arakaki Kyoko, Shiroma Mayumi , Miyazato Masaru, Nakachi Noriya , Tomiyama\nRyosaku , Hokama Akira . The volcano sign and mucus outflow by colonoscopy - Low grade appendiceal mucinous\nneoplasm . Rev Esp Enferm Dig 2024. doi: 10.17235/reed.2024.10841/2024.\nThis is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we\nare providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of\nthe resulting proof before it is published in its final form. Please note that during the production process errors may be\ndiscovered which could affect the content, and all legal disclaimers that apply to the journal pertain.\n\nCC 10841\nThe volcano sign and mucus outflow by colonoscopy - Low grade appendiceal\nmucinous neoplasm\nYuko Tasato1, Yoshiki Chinen2, Kyoko Arakaki3, Mayumi Shiroma¹, Masaru Miyazato1,\nNoriya Nakachi1, Ryosaku Tomiyama1, Akira Hokama4\nDepartments of 1Gastroenterology, 2Surgery, 3Pathology and 4Medical Checkup. Naha\nCity Hospital. Naha, Okinawa. Japan\nCorrespondence: Yuko Tasato\ne-mail: yukkomanbo0925@gmail.com\nKeywords: Colonoscopy. Volcano sign. Low grade appendiceal mucinous neoplasm.\nConflict of interest: the authors declare no conflict of interest.\nDear Editor,\nAn 82-year-old female presented to a clinic with painless hematochezia. Her medical\nhistory was unremarkable and was referred to our hospital for further examination.\nPhysical examination revealed was unremarkable and laboratory tests were normal.\nColonoscopy revealed a submucosal tumor-like mass approximately 15 mm in size in\nthe cecum. The appendiceal orifice was identified in the center of the prominence,\nshowing the volcano sign (Fig. 1A and B). The yellowish mucus was discharged from the\norifice like a lava flow, the so-called mucus outflow, when palpated with the biopsy\nforceps (Fig. 1C). As the abdominal computed tomography (CT) scan showed no\nabnormal findings suggestive of appendiceal enlargement, distant metastasis, or intra-\nabdominal tumor, she underwent laparoscopic appendectomy based on the diagnosis\nof appendiceal mucinous neoplasm. The pathological diagnosis was low grade\n\nappendiceal mucinous neoplasm (LAMN) without destructive invasion (Fig. 1D-F). The\npatient has not suffered recurrence or peritoneal pseudomyxoma for five years after\nsurgery.\nDiscussion\nLAMN is a clinical entity characterized by the absence of infiltrative growth or\ndestructive invasion but recognized as a borderline malignant tumor because it has a\npropensity for peritoneal dissemination, resulting in peritoneal pseudomyxoma (1).\nThere are two types of LAMN: type I, in which mucus or endothelial cells remain in the\nappendiceal lumen, and type II, in which there is a high risk of deep submucosal\ninvasion and transformation to peritoneal pseudomyxoma (1,2). The present case\ncorresponded to type I. The differential diagnosis includes appendiceal polyps,\nlipomas, neuroendocrine neoplasms, and endometriosis (2,3), none of which are\nassociated with the mucous outflow from the appendiceal orifice. There were also no\nfindings suggestive of lipoma or neuroendocrine neoplasia on CT scan. Pathognomonic\nfeatures of the mucus outflow may be helpful in differentiating these tumors (3,4), as\nshown here. Treatment is generally surgical resection, but there are no clear criteria\nregarding the surgical technique, and appendectomy or partial cecal resection is\nconsidered to be sufficient in cases of probable adenoma (1,2,5). In conclusion, our\ncase underscores the importance of the volcano sign and the mucus outflow in the\npreoperative diagnosis of appendiceal mucinous neoplasm.\nReferences\n1. Umetsu SE, Kakar S. Staging of appendiceal mucinous neoplasms: challenges\nand recent updates. Hum Pathol 2023;132:65-76. DOI:\n10.1016/j.humpath.2022.07.004\n2. Shaib WL, Assi R, Shamseddine A, et al. Appendiceal mucinous neoplasms:\ndiagnosis and management. Oncologist 2017;22:1107-16. DOI:\n10.1634/theoncologist.2017-0081\n\n3. Hamilton DL, Stormont JM. The volcano sign of appendiceal mucocele.\nGastrointest Endosc 1989;35:453-6. DOI: 10.1016/s0016-5107(89)72860-1\n4. Vashistha N, Deo A, Singhal D. Gastrointestinal: mucocele appendix with\natypical “volcano sign”. J Gastroenterol Hepatol 2022;37:45. DOI: 10.1111/jgh.15541\n5. Assarzadegan N, Montgomery E. What is new in the 2019 World Health\nOrganization (WHO) classification of tumors of the digestive system: review of selected\nupdates on neuroendocrine neoplasms, appendiceal tumors, and molecular testing.\nArch Pathol Lab Med 2021;145:664-77. DOI: 10.5858/arpa.2019-0665-RA\n\n.\n\n\n\nFig. 1. A. The appendiceal orifice was identified in the center of the prominence,\nshowing the volcano sign. B. The volcano sign appeared clearly with indigo carmine\ndye. C. The yellowish mucus was discharged from the orifice like a lava flow, the so-\ncalled mucus outflow, when palpated with the biopsy forceps. D. The resected\nappendix was filled with viscous fluid. The mucinous lesion was located in the proximal\nlumen (arrow) of the vertical incised appendix. E. The mucosa was replaced by\nmucinous undulating epithelial proliferation (H&E ×12.5). F. Higher-power view shows\nthe epithelium lined by tall columnar cells and cytoplasmic mucin vacuoles\ncompressing the nucleus, making the diagnosis of low grade appendiceal mucinous\nneoplasm (H&E ×100).","source_license":"public-domain-us","license_restricted":false}