Case Report Primary intrasellar melanotic ependymoma successfully treated by combined transsphenoidal and gamma knife surgeries: case report and review

Ependymoma accounts for 6-12% of all intracranial tumors, but only 6 cases of melanotic ependymoma have been reported. Sellar ependymomas are also extremely rare, with only 5 cases reported in the pituitary fossa. A 26-year-old man presented with an extremely rare case of primary intrasellar melanotic ependymoma manifesting as consistent frontalgia. Magnetic resonance imaging showed a sellar lesion slightly compressing the optic chiasm upwards with various sizes and shapes of significant hypointense areas, initially suspected to be flow voids, in and on the surface of the lesion. Transsphenoidal surgery was performed, resulting in gross total removal of the tumor. Postoperative histological examination disclosed that the tumor cells had round to semioval nuclei without specific structures. Nucleoli were distinct, and frequent brown pigmentations were seen in the cytoplasm. Immunohistochemical examinations revealed diffuse positive reactions to vimentin, glial fibrillary acidic protein, and CAM5.2, and focal positive reaction to HMB-45. Type IV collagen was negative, and epithelial membrane antigen showed dot-like positive reaction at the perinuclear area. Gamma knife surgery was applied, and the patient has been healthy without tumor recurrence for 24 months. This extremely rare variant of ependymoma should be included in the differential diagnosis if melanin production is suspected.