Cerebral medulloepithelioma with bone, cartilage, and striated muscle. Light microscopic and immunohistochemical study.

A two-and-a-half-year-old girl had a cerebral medulloepithelioma with histologic evidence of ependymal, astroglial, oligodendroglial, and neuroblastic differentiation, as well as islands of cartilage and bone, and a microscopic focus of striated rhabdomyoblasts. Immunohistochemical staining for glial fibrillary acidic protein and S-100 protein with the peroxidase-antiperoxidase technique revealed positive staining in the various differentiating neural elements of the tumor. Mesectodermal differentiation, or the production by neuroectoderm of tissues usually considered to be mesodermal, is being increasingly recognized in the fields of embryology and tissue culture. Although this is the likely explanation for the composition of this tumor, other possibilities are considered as well.