[Germinoma originating in the basal ganglia--report of 2 cases].

We reported two cases of germinoma originating in the basal ganglia among the 50 cases of intracranial germinoma which were experienced at the Department of Neurosurgery, Hokkaido University Hospital. (Case 1) A 8-year-old boy was admitted to our hospital in October 1977, because of precocious puberty and left hemiparesis. Plain CT showed an irregularly-defined high density lesion in the right basal ganglia, which had several low density spots and was moderately enhanced on contrast CT. Endocrinological examination by radioimmunoassay revealed abnormally high level of serum luteinizing hormone and scanty level of serum follicle stimulating hormone. Beta-subunit of human chorionic gonadotropin (HCG) showed 46.4 ng/ml. Following radiation, the lesion on CT disappeared and beta-subunit turned to be in the normal range. It was concluded that the precocious puberty was due to hypersecretion of HCG by the tumor. About 2 years after the first admission, the tumors were disseminated to the spinal cord, followed several months later by the intracranial recurrence. The neurosurgical exploration was performed to both intracranial and spinal tumor lesions, which were proved to be germinoma by histological examination. Postoperative course was uneventful without recurrent signs. (Case 2) A 10-year-old boy was admitted to our hospital with 6-month history of right hemiparesis in February, 1979. CT at the first admission disclosed a slight high density lesion in the left basal ganglia, which had low density area suggesting cyst formation and was moderately enhanced on contrast CT. CT after one year showed multiple cysts in the tumor and displacement of neighboring structures. In February, 1980, a piece of the tumor was removed under bifrontal craniotomy and histologically diagnosed to be germinoma. Following radiation, the tumor disappeared on CT and his clinical features improved. In August, 1981, no recurrent signs were noted. From our 2 cases and review of the literature, it can be concluded that germinoma originating in the basal ganglia is rare and have high radiosensitivity as well as germinoma arising in the other sites, and common symptoms and signs are hemiparesis in all cases, not accompanied by intracranial hypertension in the early stage.