An intrasellar germinoma with normal tumor marker concentrations mimicking primary lymphocytic hypophysitis.

Intracranial germinomas (GE) are malignant neoplasms most commonly found in the suprasellar region, which may cause anterior and particularly posterior pituitary hormone deficits with central diabetes insipidus (DI). Differential diagnosis of pituitary stalk thickening includes granulomatous, inflammatory, infectious, and neoplastic lesions. Although careful analysis of clinical, laboratory, and imaging findings may facilitate the diagnosis, transsphenoidal biopsy is indicated to confirm the disease, as the correct diagnosis directs the appropriate treatment.