Germinoma in the fourth ventricle.

A 33-year-old male presented with trigeminal, abducens, and facial nerve pareses associated with cerebellar signs. Magnetic resonance imaging showed a homogeneously enhanced mass occupying the lower half of the fourth ventricle and attached to the floor of the fourth ventricle. The mass was subtotally removed. The histological diagnosis was pure germinoma. Neuro-imaging cannot distinguish germinoma in the fourth ventricle from ependymoma. Germinoma in the fourth ventricle is extremely rare and requires histological differentiation from ependymoma to determine the indications for adjuvant irradiation and/or chemotherapy.