Ectopic Germinoma in the Corpus Callosum with Severe Restrictive Anorexia: Case Report and Review of Literature

BACKGROUND: Intracranial germ cell tumors are a rare group of neoplasms constituting 1% to 2% of primary intracranial tumors in North America and Europe. Germinomas of the corpus callosum are exceedingly rare, accounting for only 0.7% of all intracranial germ cell tumors. CASE DESCRIPTION: We report a case of germinoma in the corpus callosum of a 17-year-old woman with a 2-year history of personality change, anorexia, amnesia, hypersomnia, and depression. Magnetic resonance imaging showed a well-circumscribed, heterogeneous mass measuring 2.9 x 5 x 3.1 cm, with multiple cystic areas and heterogeneous enhancement with gadolinium. It arose in the corpus callosum and extended to the fornix and frontal lobes. There was mild perilesional edema but no evidence of hypothalamus or hippocampus involvement. No spinal drop metastases were visualized on magnetic resonance imaging. Cerebrospinal fluid and serum levels of alpha-fetoprotein, beta-human chorionic gonadotropin, carcinoembryonic antigen, and placental alkaline phosphatase were all normal. Immunohistologic staining of tumor cells was positive for OCT3/4, placental alkaline phosphatase, and CD117 and negative for CD30 and GPC3. Radiotherapy led to a substantial decrease in tumor size. CONCLUSION: This is a case of germinoma arising in the corpus callosum that presented clinically with an eating disorder manifested as restrictive anorexia.