Anorectal melanoma: an uncommon and aggressive disease.

Department of Gastroenterology, Centro Hospitalar do Porto – Hospital de Santo António, Porto, Portugal Correspondence: Dr Maria João Magalhães, Rua Dr Manuel Rodrigues de Sousa, 21 5o D, 4450-181 Matosinhos, Porto, Portugal. Telephone 351-93-312-8979, e-mail [email protected] Received for publication August 1, 2014. Accepted August 4, 2014 CASE PRESENTATION A 74-year-old woman was admitted to hospital in August 2010 for community-acquired pneumonia. Laboratory investigations revealed iron deficiency anemia (hemoglobin 104 g/L) and a thoracic computed tomography scan revealed scattered bilateral nodular opacities compatible with pulmonary metastasis of unknown primary site. In the diagnostic workup, the colonoscopy revealed a 40 mm vegetating lesion with a brownish surface at the distal rectum involving the anorectal transition (Figures 1 and 2). Histological analysis revealed an ulcerated malignancy with pleomorphic epithelioid cells and abundant melanophages (Figures 3 and 4). Immunohistochemical staining was positive for S-100, HMB-45 and Melan-A proteins, establishing the diagnosis of anorectal melanoma. She also had brain metastases. Due to the global status, symptomatic treatment was proposed. The patient died six months later.