Primary Melanoma of the Sphenoid Sinus

Background and Aim: Malignant melanoma is a very rare disorder in the paranasal sinuses. It accounts for less than 1% of all malignant melanomas and less than 3% of paranasal malignancies. It is also rare for a melanoma to metastasize to this region. However, a thorough investigation is always needed to rule out a metastasis as opposed to a primary sinonasal melanoma. Malignant melanomas arising from the sphenoid sinus with unilateral invasion of the skull base are also extremely rare. Whether the sella turcica or sphenoid sinus is the site of origin is difficult to determine based on neuroradiological findings. These tumors have poor prognosis owing to higher rates of locoregional recurrence and distant metastasis. Case Report: A 74-year-old woman presented to our department complaining of occipital headache and diplopia. Clinical examination revealed a VIth nerve palsy and diplopia. Both CT and MRI scans revealed an expansive right sphenoid sinus mass with invasion of the skull base that seemed inoperable. Endoscopic biopsy from the sphenoid sinus was performed, and the histology report revealed a malignant melanoma. A thorough investigation for another primary site was negative. As the tumor was progressing rapidly, the patient suffered several cranial nerve palsies. The patient underwent radiation. Conclusion: Malignant melanoma is a rare tumor in the paranasal sinuses. Thorough investigation is needed to exclude the possibility of a metastatic lesion. Various treatment modalities have been employed over time, but the ideal treatment approach still remains a matter of debate.