Sinonasal Malignant Melanoma Variant: A Case Report

Abstract

Sinonasal malignant melanoma (SMM) is a rare malignant tumour among head and neck cancers predominantly found in adults 60 years and above. The commonly reported symptoms for sinonasal tumour lesions are nasal obstruction and recurrent, painless epistaxis as the symptoms are non-specific and can delay the diagnosis. Moreover, melanoma has a poor prognosis regardless of its location. We report an 86-year-old female patient presenting with recurrent, painless epistaxis from the nasal cavity. Anterior rhinoscopic examination revealed a bluish-black, bleeding mass completely obstructing the left nasal nare. Contrast-enhanced computed tomography of the nasal cavity and sinus region showed a polypoidal soft tissue attenuation with heterogeneous enhancement completely filling the left nasal cavity. The patient underwent endoscopic excision. Histopathology of the specimen showed a small, round and blue cell tumour which immunohistochemistry found to be positive for S100 and HMB 45. After surgical resection, the patient received chemotherapy and radiotherapy. Sinonasal malignant melanoma is a rare, aggressive tumour that has a very poor prognosis. Contrast-enhanced computed tomography of the nasal cavity and paranasal sinuses is the imaging modality of choice which reveals the enhancing mass. There is no optimal management strategy for SMM. Surgical resection is the first-line treatment but is limited due to the complex anatomy of the sinonasal region.

Keywords: blue cell tumour; head & neck cancer; hemosiderin; melanin; melanoma.

Figure 1. Coronal CT scan showing a mass (red arrow) extending superiorly to the ethmoid sinus

Figure 2. Immunohistochemistry of the biopsy showing malignant melanocytes positive for S100

Figure 3. Immunohistochemistry of the biopsy showing malignant melanocytes stain positive for HMB 45