Primary Anorectal Amelanotic Melanoma: The First Case Report from Saudi Arabia

Autor: Khaled Ali Baniyaseen, Muhammad Saeed, Ahmed Omar Albonni, Bothaina Mohammed Abdulshakour, Ghida Dairi, Faisal A. Al-Allaf, Mohiuddin M. Taher
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Middle East Journal of Digestive Diseases, Vol 11, Iss 3, Pp 166-173 (2019)
Druh dokumentu: article
ISSN: 2008-5230
2008-5249
DOI: 10.15171/mejdd.2019.144
Popis: Anorectal melanomas are exceptionally uncommon and only 30% of anorectal melanomas are amelanotic. We report here a case of an anorectal amelanotic melanoma in a female patient. An 84-year-old patient complained of anal mass for 3 months. On examination, there was a 7.0 cm mass prolapsing through the anus that was pale-pink in color. Abdominal, pelvic, and chest computed tomography (CT) showed rectal wall thickening with an eccentric polypoid soft tissue density mass, and left inguinal and presacral lymph node enlargement along with a small nodule in the lower lobe of the left lung, likely representing metastatic deposit. Microscopic examination revealed a piece of skin with hyperplastic squamous epithelium with surface ulceration. The dermis and underlining tissue were showing infiltration by malignant sheets and nests of ovoid and spindle shape cells with prominent nucleolus and high mitotic s. Immuno-staining for HMB-45, S-100, and Melan-A was positive, and it was negative for P63, CK 5/6, and Pan-CK, thus confirming it as an anorectal amelanotic melanoma, and not an epithelial tumor. This is the first case of an amelanotic anorectal melanoma reported from Saudi Arabia.
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