Anal melanoma is a rare melanocytic malignancy, which roughly comprises 2% of all anorectal malignancies.1 2 The anal area is the most common site for primary gastrointestinal melanomas.2 Patients with anal melanomas commonly complain of bleeding, anal pain and mass, tenesmus, and changes in bowel habits. In cases with metastases, symptoms such as weight loss, anemia, fatigue and bowel obstruction could be present.2 Risk factors of anal melanoma include old age, multiple sexual partners, anal sex, smoking, history of other malignancies (i.e., cervical, vulvar, or vaginal cancer), activation of the receptor tyrosine kinase c-Kit, and family history of malignancies.3 4 The diagnosis of anal melanoma is established through biopsy—usually done with colonoscopy—and immunological staining.5 HMB-45 is the immunological stain commonly used for the detection of both primary and metastatic melanomas.6 Endoscopic ultrasonography also helps to characterize lesions and assess the depth of infiltration.7
Melanoma ; Thyroid Cancer, Papillary