Primary Malignant Melanoma of the Sphenoid Sinus as a Crucial Differential Diagnosis of Skull Base Tumors: A Case Report.

A 79-year-old man presented with progressive ptosis, diplopia, and headaches, which led to the diagnosis of a rare primary malignant melanoma of the sphenoid sinus. Imaging revealed extensive bone destruction and aggressive tumor behavior. The rarity of primary malignant melanoma in the sphenoid sinus complicates early detection. Despite undergoing surgical decompression, immunotherapy, and radiation therapy, the tumor rapidly recurred, necessitating supportive care. This case highlights the need for neurosurgeons to include primary malignant melanoma in the differential diagnosis of skull base tumors, particularly in the sphenoid sinus, due to its potential for aggressive local invasion and significant impact on critical neurovascular structures. Early recognition and intervention are crucial for managing this rare and aggressive malignancy effectively.