Anorectal malignant melanoma in a hemorrhoidal nodule: a diagnostic and therapeutic problem

Anorectal malignant melanoma (ARMM) is an extremely rare condition, often misdiagnosed and mistreated until development of metastatic disease. Clinical presentation mimicking hemorrhoids is a well-known pitfall. We present a male patient with hemorrhoidal nodules who was referred to the policlinic of dermatology for management of anal pruritus. A dark macule was detected over one of the hemorrhoidal nodules histologically verified as melanoma. Subsequent CT and PET/CT showed lymph nodes involvement and the patient underwent wide local excision (WSE) followed by abdominoperineal resection (APR). The rarity of ARMM does not allow for establishment of a validated staging system, placebo-controlled treatment trials and management guidelines adoption. The current treatment for the condition is surgical excision, using different techniques according to the stage of the disease and depth of invasion. The prognosis and overall survival are poor, but recent genetic studies give promising results for molecular targeting. Awareness for this disease is indispensable, as early recognition could result in improved survival and quality of life.