Abstract
Sinonasal malignant melanoma is a rare, aggressive tumor, associated with a poor prognosis, accounting for 8-15% of all head and neck melanomas and 0.5-2% of all melanomas. The diagnosis is given by histopathological and immunological examination. Elective treatment consists of surgical excision with free resection borders, and adjuvant chemotherapy / radiotherapy / immunotherapy / checkpoint inhibitors can be used to control local recurrence and distant metastases. We chose to present the case of an unresectable ethmoidal malignant melanoma at the time of diagnosis, pembrolizumab treatment converting it to resectability, with improving patient’s quality of life, even if the patient developed an adrenal metastasis.