ABSTRACT
We present a case of cerebral germinoma that occurred in the basal ganglia with progressive hemiparesis. A 10-year-old boy was referred to our hospital complaining of progressive right hemiparesis and decreased mental functions. Brain MRI showed left cerebral hemiatrophy and high signal intensity in left thalamus, basal ganglia, cerebral peduncle, and pons. However, no mass or enhancement was observed. 11C-Methionine positron emission tomography showed discernable hot uptake in the left basal ganglia and thalamus. Stereotactic biopsy, with a guide of 11C-Methionine positron emission tomography, was performed and the diagnosis of pure germ cell tumor was determined. 11C-Methionine positron emission tomography is useful for localization of a suspicious tumor in patients with cerebral hemiatrophy without overt mass or enhancing lesions in brain MRI.