title: Primary anorectal malignant melanoma: an uncommon anorectal pathology.
abstract: Anorectal malignant melanoma (AMM) is most common primary melanoma of gastrointestinal tract, accounting for 0.05% and 1% of all colorectal and anal cancers. We reported an 85 year-old woman with no significant past medical history who presented two-month period of rectal bleeding, abdominal pain, tenesmus and 2kg weight-loss. Laboratory markers were unremarkable, although rectal examination revealed two small haemorrhoids and a firm, non-obstructing mass in the lower rectum. Colonoscopy confirmed presence of an ulcerated pigmented neoplasm arising at dental line [A,B]. No distant metastases were found on computed tomography [C] although presented metastatic regional lymph nodes on pelvic MRI [D]. Therefore, abdominoperineal resection was performed, confirming loco-regional disease. Histopathology showed malignant melanoma with positive stains in immunohistochemistry for protein S100, HMB-45 and Melan-A [E,F,G,H] and stained negative for c-Kit.
authors.affiliation: Unidad de Endoscopia. Aparato Digestivo, Complejo Hospitalario de Navarra, españa.
authors.forename: José Francisco
authors.initials: JF
authors.lastname: Juanmartiñena Fernández
authors.affiliation: Digestivo, Complejo Hospitalario de Navarra, España.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández-Urien
authors.affiliation: Departamento de Anatomía Patológica, Complejo Hospitalario de Navarra, españa.
authors.forename: Alicia
authors.initials: A
authors.lastname: Córdoba
mesh_terms: D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology*; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology*; D000096142:Cutaneous Malignant Melanoma