[Gamma knife radiosurgery for malignant melanoma in the paranasal sinuses: case report].

A case of malignant melanoma in the paranasal sinuses, successfully treated with gamma knife stereotactic radiosurgery, is reported. A 90-year-old man with left periorbital swelling was referred to our hospital for gamma knife radiosurgery. He had a 4-month history of left periorbital swelling and ophthalmalgia, but he was treated conservatively due to his age. CT showed a large mass with bone destruction located in the nasal cavity, paranasal sinuses, and orbita. A 15 Gy peripheral dose was administered to the upper portion of the tumor with the gamma knife technique, at the 50% isodose line using a 18 mm collimator (21 shots). Seven months after radiosurgery, his left periorbital swelling was improved markedly, and CT showed a significant reduction in the volume of the tumor. Gamma knife radiosurgery is a feasible treatment for malignant melanoma in the paranasal sinuses. It provides excellent quality of life, less injury to the patient, and fewer side effects than other treatment strategies.