1986 Volume 26 Issue 1 Pages 30-34
Primitive neuroectodermal tumors are very rare, malignant tumors of the cerebrum of young individuals, predominantly composed of undifferentiated cells, with differentiation along either neuronal or glial lines. Primary cystic tumors of the thalamus are also very rare and have been reported only in children. The case described here is the first report of a cystic tumor arising from the thalamus of an adult and containing pathologic features of a primitive neuroectodermal tumor. According to the literature, and in our clinical experience as well, primitive neuroectodermal tumors tend to diffusely disseminate into the subarachnoid space, which presents several diagnostic and therapeutic problems.