Sinonasal Mucosal Melanoma

Sinonasal mucosal melanoma (SNMM) is a rare aggressive tumor often diagnosed at advanced stage. SNMM is associated with a greater than 50% rate of recurrence and a disease-specific 5 year survival rate of less than 25%. Sinonasal anatomy may contribute to difficulty in early detection; SNMM is usually asymptomatic until bulky and polypoidal. Presenting clinical symptoms are often nonspecific. The histopathologic features of SNMM are quite variable and immunohistochemical analysis is usually necessary for diagnosis. Mucosal melanomas lack ultraviolet signature, have low somatic mutational burden, and are reported to have more genomic instability manifested as structural variants, deletions, and amplifications.