Introduction:
Primary mucosal melanomas are rare, biologically aggressive neoplasms, with very poor outcomes. They account for 1.4% of all melanomas and only 0.3% of new cancer diagnoses [1]. The distribution of head and neck, female genital tract, anal/rectal, and urinary tract sites is 55.4%, 18.0%, 23.8%, and 2.8% respectively[2]. The median age of presentation is the seventh decade, with a tendency for women to be affected more than men[2].
In the head and neck region, there seems to be a predominance of the disease in the sinonasal region, accounting for 59-80% of cases[3]. Mutations associated with mucosal melanoma are to this day poorly understood. A paper by Nassar et. al. published in 2020, looking at the mutational landscape of mucosal melanoma, showed, using targeted sequencing, whole-exome sequencing, and whole-genome sequencing, that the mutation is unknown in 44% of cases. However, SF3B1 gene was implicated in 15% of cases, KIT gene in 13%, NF1 in 14%, NRAS in 8%, and BRAF in 6% [4].
The overall 5-year survival is poor, with one paper citing a 21.7% rate in 695 patients [5]. Treatment of mucosal melanoma has been subject to multiple different trials, some of which include surgery alone, surgery with chemotherapy, surgery with radiotherapy, surgery with chemo radiotherapy, and finally with or without immunotherapy. Surgery remains the primary therapeutic intervention given that complete resection is feasible in a set anatomical location. Treatment with immunotherapy is novel, and so the literature is lacking in studies proving efficacy of immunotherapy treatment.