Germinoma with a granulomatous reaction. Problems of differential diagnosis.

The patient was a 6 year-old girl with a progressive loss of visual acuity. Magnetic resonance imaging showed a suprasellar mass lesion with enhanced gadolinium which was resected. Histopathological study showed a remarkable granulomatous reaction, but a diagnosis was difficult. However, immunohistochemical study showed a few cells that were positive for placental alkaline phosphatase and it was diagnosed as germinoma. Intracranial germinoma with a remarkable granulomatous reaction is rare. However, when germinoma is suspected clinically, an immunohistochemical study is able to identify germinoma even if granulomatous disease is diagnosed histopathologically.