Primary Germinoma Originating from the Insular Lobe: A Case Report and Review of the Literature.

Abstract

Primary intracranial germinomas occurring in the cerebral hemisphere are extremely rare, with only a few reported cases in the literature. We describe an unusual case of a primary germinoma that developed in the insular lobe, with little involvement in the basal frontal lobe. A 19-year-old man presented with headache and vomiting. Magnetic resonance imaging showed a solitary, ring-like enhanced lesion in the left hemisphere, and a preliminary diagnosis of glioma was made. Surgery was performed, and the diagnosis of germinoma was made based on the histopathologic results. The causes of ectopic germinomas of the midline structures of the brain are still unclear, but the theory of misplacement may partially clarify this phenomenon. Reflecting a lack of definitive management guidelines for atypical germinoma, the present patient was treated with focal radiotherapy around the lesion after surgery and achieved remission by 34 months postoperatively.