Primary mucosal melanoma masquerading as nasal polyp: A diagnostic challenge

Abstract

Nasal mucosal melanoma (MM) is a rare and aggressive tumor, first described by Lucke in 1869. It accounts for 0.5%–2% of all melanomas. Its incidence is more in fair skinned individuals, and most commonly seen in the mean age of 60 years with slight male predominance. MMs are associated with poor prognosis and overall less survival rates as symptoms develop slowly; therefore, many patients are lately diagnosed. An Indian female in her early 50s came to the ear, nose, and throat outpatient department with complaints of bleeding from her nose for 20 days and mass in the right nasal cavity. On examination, a dirty black mass arising from the septum and deviated nasal septum to the right side were noted on rhinoscopy. Contrast-enhanced computed tomography showed features of nasal polyp. Fine-needle aspiration cytology was performed and found to be inconclusive. A punch biopsy was done and sent for histopathological examination (HPE), tiny biopsy showed features suggestive of melanosis with focal atypia. After 3 months, the patient reported with recurrence of nasal mass that was progressive in size. An excision biopsy was performed by endoscopic surgery under local anesthesia and sent for HPE. To confirm the diagnosis, immunohistochemistry was performed by application of S100, HMB45, and vimentin (after bleach treatment) showed diffuse strong intensity nuclear and cytoplasmic positivity in all pigmented cells. Thereafter, diagnosis of “Nasal mucosal melanoma” was awarded.

Keywords

• immunohistochemistry
• mucosal melanoma
• nasal polyp