Primary Intracranial Melanocytic Tumor Simulating Pituitary Macroadenoma: Case Report and Review of the Literature

Abstract

ABSTRACT OBJECTIVE AND IMPORTANCE: Primary intracranial melanocytic tumors are rare lesions, sellar ones being even more exceptional. So far, six melanomas and two melanocytomas have been described in an intrasellar and/or suprasellar location. CLINICAL PRESENTATION: We report on the case of a 25-year-old Caucasian woman presenting with a 4-year history of amenorrhea and an intrasellar mass with suprasellar extension suggestive of a pituitary macroadenoma. INTERVENTION: A gross subtotal resection of a hemorrhagic tumor was performed. Histological examination revealed melanin-laden pleomorphic tumor cells that tested positive for HMB-45 and S-100 and negative for cytokeratins, thus demonstrating that the tumor was a melanocytic neoplasm. An extensive workup failed to find evidence of any other primary site. The patient received no further treatment and is alive and well after 24 months of follow-up. CONCLUSION: Primary sellar melanocytic neoplasms are extremely rare lesions and present with few differential diagnoses. Deciding whether the tumor is best classified as a melanocytoma or a melanoma may prove difficult. Wide histological variations in both melanocytomas and melanomas render careful consideration of the clinical, radiological, and gross features essential in distinguishing one from the other.