Germ cell tumor presenting as sellar mass with suprasellar extension and long history of hypopituitarism

Primary central nervous system germ cell tumors are rare neoplasms usually located in the pineal and/or suprasellar region. Pure germinomas do not usually secrete beta-human chorionic gonadotropin hormone (beta-HCG) or alpha-fetoprotein (AFP) and diagnosis is made a few weeks or months after beginning of symptoms.

Here we report a case of a pure germinoma in a 20 year-old woman presenting as a sellar mass with suprasellar extension, abnormal serum beta-HCG and a long history of polyuria and polydipsia (4 years), that was initially diagnosed as a pituitary macroadenoma.

This presentation highlights the importance of thinking in alternative diagnosis to pituitary adenoma when diabetes insipidus is the initial symptom.