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.