[Rapidly enlarging supratentorial ependymoma in a child presenting initially with a small calcified lesion: case report].
The authors report an unusual case of a 11-year-old boy whose supratentorial ependymoma showed rapid growth. He had had generalized convulsive seizures when he was 9 years old. On an initial CT scan a small calcified lesion was identified adjacent to the right sensorimotor cortex. Repeated CT scans showed no interval change in the size of the tumor for 16 months. Then, he suffered an acute onset of left hemiparesis. The neuroimaging studies demonstrated a huge tumor with a large cyst in the right parietal region which had not been observed on CT scan 7 months before. Total removal of the tumor was performed and the histopathological diagnosis was ependymoma with no evidence of malignancy. However, MIB-1 staining of the specimen revealed a high index of 1 proliferative potential up to 25% in some area. The high score of MIB-1 staining correlated well with the rapid clinical course of this histologically benign ependymoma. The small calcified lesion demonstrated on the initial CT scan in this case is considered to have been a low grade ependymoma and to have abruptly transformed into a higher grade, one resulting in rapid enlargement. The authors stress that small intracranial calcified lesions should be carefully followed up by repeated neuroimaging studies at short intervals.