Primitive neuroectodermal tumor (neuroepithelioma) of spinal nerve root -- Report of an adult case and establishment of a cell line.

A case of primitive neuroectodermal tumor arising in the cervical nerve root of a 28-year-old man is presented. Histologically, the tumor was characterised by proliferation of primitive neuroectodermal cells and formation of numerous Homer-Wright type rosettes. A cell line (Nagai line) was established from the tumor. Electron microscopic examination of Nagai cells revealed numerous microrosette formation with microvilli-like cytoplasmic processes projecting into the central lumina. Neurosecretory granules appeared in the cytoplasmic processes when Nagai cells were treated with dibutyryl cyclic AMP. Primitive satellite cells which completely surrounded other tumor cells with their tongue-like slender cytoplasmic processes were also found. Histogenesis of this unique tumor was discussed comparing with the neuroblastoma of sympathetic nervous system, medulloblastoma of the central nervous system, and with the tumors induced by Adenovirus type 12 in animals. It was concluded that the tumor was neuroepithelioma derived from a primitive stem cell of neural crest origin which possesses the bipotency to differentiate toward either neuroblastic or neurilemmal line.