Metastatic mucosal melanoma: imaging patterns of metastasis and recurrence

Purpose: Mucosal melanoma is a rare but aggressive subtype of melanoma with unique clinicopathologic features. We hypothesize that mucosal melanoma shows predilection for separate and unique metastatic pathways. Materials and methods: This was a retrospective analysis of 19 patients (5 men and 14 women; median age 60 years, range 38–76 years) with metastatic mucosal melanoma presenting to a tertiary oncology center between 2005 and 2010. We performed a review of medical records and histologic and imaging studies to evaluate the natural history, metastatic patterns and the role of imaging in the management of patients with advanced mucosal melanoma. Results: At presentation, disease was confined to the primary site (58%, n = 11) or to the regional lymph nodes (32%, n = 6) in most patients. The most common site of metastasis was the lungs (89%, n = 16), followed by the liver (67%, n = 12) and peritoneum (44%, n = 8). Sinonasal melanoma preferentially spread to the liver (100%, n = 4), vaginal melanoma to the lungs (100%, n = 7) and anal melanoma to the inguinal lymph nodes (100%, n = 4). Conclusion: Pathways of metastatic spread in mucosal melanoma may differ from other forms of melanoma and between different primary sites of mucosal origin.