[Basal ganglia germinoma treated with interstitial brachytherapy; case report].

A case of primary intracranial germinoma in the left basal ganglia treated with interstitial brachytherapy was reported. A 15-year-old boy was referred to our hospital for evaluation of right hemiparesis. A CT scan showed a slightly hyperdense mass with multiple cystic low density in the left basal ganglia. The mass was heterogeneously enhanced after intravenous administration of contrast material. T1 weighted image showed a slightly hyperintense mass with cystic components and the mass was heterogeneously enhanced with Gd-DTPA. T2 weighted MR image showed a mixed intensity mass and peritumoral edema. Stereotactic needle biopsy and implantation of 3 catheters for interstitial brachytherapy were performed simultaneously using BRW CT guided stereotactic apparatus. After the histological diagnosis was confirmed to be two cell pattern germinoma, 9 iridium-192 seeds were inserted into the catheters and maintained for 10 days to give 35Gy of irradiation at the tumor periphery. Subsequent CT scans showed marked tumor regression and the clinical symptoms were improved. Germinoma originating in the basal ganglia is rare and hard to diagnose previous to biopsy. Histological confirmation is essential before initiation of treatment because germinoma is commonly thought to be radiosensitive tumor. The interstitial brachytherapy enables selective irradiation of the tumor and actually causes no complications such as bone marrow suppression or cerebral atrophy. The neuroradiological findings, especially of CT scan and MRI, were presented and the strategy for treatment of germinoma in basal ganglia was discussed.