Pineal germinoma with a prominent epithelioid cell granuloma component: case report.

A 20-year-old man presented with a rare case of germinoma with a large component of epithelioid cell granuloma manifesting as oscillopsia. Magnetic resonance imaging demonstrated a mass in the pineal region with homogeneous enhancement with gadolinium. Craniotomy was performed, ending in biopsy. The initial histological diagnosis was epithelioid cell granuloma, but systemic investigation detected no evidence of granulomatous disorder. A revised diagnosis of germinoma was based on positive immunohistochemical staining for placental alkaline phosphatase (PLAP) and c-kit. Histological diagnosis is sometimes incorrect if granulomatous reaction is dominant. Immunohistochemical staining for PLAP and c-kit should be performed if germinoma is clinically suspected.