Primitive neuroectodermal tumors of the brain in children

Predominantly undifferentiated tumors occurring in the cerebrum of young individuals are referred to as “primitive neuroectodermal tumors.” Twenty-three of these cases were collected which had certain common features. Grossly they tended to be cystic and compressed adjacent brain. Microscopically they were malignant-appearing and demonstrated a prominent mesenchymal component. Sixteen cases showed focal evidence of glial and/or neuronal-appearing differentiation. It is suggested that the mesenchyme is also an aspect of tumor differentiation. The biologic behavior of these tumors was malignant, with an average duration of 18 months from onset of symptoms to death.