Primary anorectal melanoma: a case report

ABSTRACT

Anorectal melanoma is a rare but highly lethal malignancy. Clinical symptoms are non-specific and treatment is still debated. The aim of this study was to report a case concerning diagnostic and management of Anorectal melanoma. A 66-year-old man was admitted in our surgical unit with a 3-month history of pain and rectal bleeding. Rectal examination revealed a tender mass arising from the 5 o'clock position of the anal canal that bled on touch. A provisional diagnosis of rectal polyp was made and it was removed by local excision under general anaesthesia. Histopathologic examination reported it as an anorectal malignant melanoma. The postoperative course was uneventful. Extension staging showed a 15 mm nodule on the left lung. The patient underwent a metastasectomy of the left lung. No adjuvant therapy was given. He died one year later. With this case we want to illustrate that malignant melanoma can be difficult to diagnose, as patients have non-specific symptoms and histology may be misleading. Surgery remains the mainstay of treatment. Wide local excision combined with adjuvant loco-regional radiotherapy should be preferred when technically feasible. Abdominoperineal resection has to be done only in the case of large tumors or when the anal sphincter is involved. Overall 5-year survival is less than 20%. It's correlated to extension of disease regardless of initial surgical therapy