An Unusual Polypoid Septal Mucosal Melanoma: Overview and Diagnostic Pitfalls.

Sinonasal mucosa is an area of high melanocyte density compared to other mucosa-lined sites. Sinonasal mucosal melanomas (SNMM) most commonly arise from the nasal cavity and the paranasal sinuses. Due to their obscure anatomic location and lack of early symptomatology, SNMM are often diagnosed in an advanced stage. The majority of patients who present with symptoms complain of unilateral nasal dysfunction, such as obstruction and epistaxis. We hereby report a case of an 86-year-old female, who presented with a three-year history of progressive right-sided nasal obstruction and recurrent epistaxis. Posterior rhinoscopy and endoscopy revealed a polypoid, fleshy lesion whose coloration varied from mildly pigmented to amelanotic. Inverted sinonasal papilloma was included in the differential diagnosis due to MRI findings. Post-resection histopathology indicated a mucosal melanoma. Typically, amelanotic lesions are rare, more difficult to diagnose and associated with worse prognosis due to both their aggressiveness and delayed diagnosis.