[Seven cases of subependymoma. Anatomoclinical study and review of the literature].

Subependymomas are uncommon, benign, slowly growing lesions usually located in the fourth ventricle. Their morphology is characteristic, but their histogenesis remains controversial. Seven cases observed in our laboratory over a period of 7 years are reported. Most tumors were located axially in the brain stem, and symptoms were more variable than usually reported. The histological appearance was fairly uniform. Immunohistochemistry showed that the fibrillary component was composed of glial fibers. Ependymary differentiation is inconstant on electron microscopy. The pathogenesis of the lesion (tumor, hamartoma or reactive proliferation) is debated in the literature as is the histogenesis.