{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T16:34:42Z","timestamp":1787070882747,"version":"build-2736575974"},"reference-count":15,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2022,1]]},"abstract":"<jats:p>Malignant melanoma of the anorectal region is a very rare aggressive malignant neoplasm and it constitutes 1% of all malignant lesions of this area. About 70% of these lesions are pigmented, whereas 30% are amelanotic. Demonstration of immune markers of melanoma by immunohistochemistry (IHC) is required for confirming the diagnosis of amelanotic malignant melanoma. Here, we report a case of anorectal malignant amelanotic melanoma in a 65-year-old male with no medical comorbidities, who presented with chief complaints of bleeding per rectum associated with prolapsing mass per rectum of 7 months duration. On external examination and proctoscopy, three prolapsed pedunculated fungating masses were seen externally protruding out of the rectum approximately 4 cm from the anal verge. Contrast-enhanced computed tomography of the whole abdomen and pelvis was suggestive of moderately enhancing lobulated anorectal mass with large polypoidal intraluminal component arising from anorectal walls and extension into mid-lower rectum with liver and locoregional lymph nodes metastasis. The patient was taken up for palliative local excision. Per-operatively, three large irregular highly vascular pedunculated rectal growth was seen. The growth was excised and sent for histopathological examination. Microscopic examination of mass show spindle-to-ovoid tumor cells with hyperchromatic central to eccentric nuclei arranged in intersecting fascicles with a focal alveolar pattern. The large number of atypical mitotic figures (40-50\/10 High Power Field (HPF)) was seen along with areas of necrosis and the presence of few bizarre binucleated and multinucleated giant cells. A differential diagnosis of malignant amelanotic melanoma was given along with undifferentiated carcinoma, gastrointestinal stromal tumor, and Non-Hodgkin's lymphoma. On IHC, the tumor cells were reactive for HMB45, S-100, and SOX-10. Thus a diagnosis of malignant amelanotic melanoma was confirmed. The patient had symptomatic improvement.<\/jats:p>","DOI":"10.4103\/jcrt.jcrt_461_20","type":"journal-article","created":{"date-parts":[[2023,1,27]],"date-time":"2023-01-27T10:31:54Z","timestamp":1674815514000},"page":"249-252","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":9,"title":["Anorectal malignant amelanotic melanoma: Report of a rare aggressive primary tumor"],"prefix":"10.4103","volume":"18","author":[{"given":"Musharraf","family":"Husain","sequence":"first","affiliation":[{"name":"Department of General Surgery, Hamdard Institute of Medical Sciences and Research, Jamia Hamdard, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tajamul","family":"Rashid","sequence":"additional","affiliation":[{"name":"Department of General Surgery, Hamdard Institute of Medical Sciences and Research, Jamia Hamdard, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mir Mujtaba","family":"Ahmad","sequence":"additional","affiliation":[{"name":"Department of General Surgery, Hamdard Institute of Medical Sciences and Research, Jamia Hamdard, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohammad Jaseem","family":"Hassan","sequence":"additional","affiliation":[{"name":"Department of Pathology, Hamdard Institute of Medical Sciences and Research, Jamia Hamdard, New Delhi, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2022,3,30]]},"reference":[{"key":"R2-20250510","first-page":"27","article-title":"Malignant tumors of the anal canal: A comprehensive review","volume":"14","author":"Karaitianos","year":"2001","journal-title":"Ann Gastroenterol"},{"key":"R3-20250510","first-page":"21","article-title":"Anorectal melanoma: A large clinicopathologic study from India","volume":"88","author":"Das","year":"2003","journal-title":"Int Surg"},{"key":"R4-20250510","first-page":"171","article-title":"Primary melanoma of the rectum: An infrequent neoplasia with an atypical presentation","volume":"7","author":"Solaz Moreno","year":"2005","journal-title":"Clin Transl Oncol"},{"key":"R5-20250510","doi-asserted-by":"crossref","first-page":"4555","DOI":"10.1200\/JCO.2002.03.002","article-title":"Sphincter-sparing local excision and adjuvant radiation for anal-rectal melanoma","volume":"20","author":"Ballo","year":"2002","journal-title":"J Clin Oncol"},{"key":"R6-20250510","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1016\/S0140-6736(02)20230-5","article-title":"Recurrent melanosis of the rectum after previous removal from the verge of the anus in a man aged sixty-five","volume":"1","author":"Moore","year":"1857","journal-title":"Lancet"},{"key":"R7-20250510","doi-asserted-by":"crossref","first-page":"2991","DOI":"10.1007\/s10620-017-4527-9","article-title":"Black is the new black: Prolapsing primary anorectal melanoma","volume":"62","author":"Jensen","year":"2017","journal-title":"Dig Dis Sci"},{"key":"R8-20250510","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1097\/CMR.0000000000000311","article-title":"Vitamin D receptor immunohistochemistry variability in sun-exposed and non-sun-exposed melanomas","volume":"27","author":"Paolino","year":"2017","journal-title":"Melanoma Res"},{"key":"R9-20250510","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1007\/s12032-014-0451-4","article-title":"Clinicopathological features, vitamin D serological levels and prognosis in cutaneous melanoma of shield-sites: An update","volume":"32","author":"Paolino","year":"2015","journal-title":"Med Oncol"},{"key":"R10-20250510","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1007\/BF02052442","article-title":"Anorectal melanoma: A 64-year experience at memorial Sloan-Kettering cancer centre","volume":"38","author":"Brady","year":"1995","journal-title":"Dis Colon Rectum"},{"key":"R11-20250510","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.1007\/BF02238576","article-title":"Changing epidemiology of anorectal melanoma","volume":"42","author":"Cagir","year":"1999","journal-title":"Dis Colon Rectum"},{"key":"R12-20250510","doi-asserted-by":"crossref","first-page":"693","DOI":"10.1007\/BF02629543","article-title":"Malignant melanoma of the anus. 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