[Unilateral thalamic tumor with atrophy of ipsilateral cortical cortex: report of a case]

Ipsilateral brain atrophy is rare in neoplastic lesions of the brain, but it has been reported in patients with a thalamic tumor. We report a Chinese boy who presented with a right focal motor seizure and right side weakness at the age of six and half years when an electroencephalogram (EEG) showed focal epileptic discharges over the left hemisphere, but computed tomography (CT) of the brain failed to reveal a definite mass lesion. The weakness became gradually worse. On admission at age 8, follow-up CT scan revealed a huge tumor (5 x 5 x 7 cm) compressing the third and lateral ventricles with mixed densities in the left thalamus and centrum semiovale. The scan after contrast infusion showed a marked enhancement of the tumor. Instead of peri-mass edema surrounding the tumor, the overlying cerebral tissue showed atrophy of the ipsilateral cortical layer. He received subtotal resection of the tumor. The pathology proved to be germinoma. A test of tumor markers revealed a high human chorionic gonadotrophin level in the blood and cerebrospinal fluid. A short course of radiotherapy and chemotherapy was given after surgery. He has been well for the past two years.