MALIGNANT SUPRATENTORIAL GLIAL-NEURONAL NEOPLASMS - REPORT OF 2 CASESAND REVIEW OF THE LITERATURE

Objective.-Malignant neoplasms exhibiting mixed populations of neurona l and glial cells occurring in the cerebral hemispheres of young adult s and children are well recognized, but rare. A confusing array of dia gnostic terms has arisen. We describe two patients with such tumors an d review the literature concerning these interesting cases. Patients.- A 21-year-old man and a 5-year-old girl presented with large, cystic, intracerebral lesions on magnetic resonance images, which proved to be composite neoplasms exhibiting malignant neurons and astrocytes. Resu lts.-The 21-year-old man had a frontal lobe mass with enhancing and no nenhancing regions, which corresponded to cerebral neuroblastoma and a naplastic astrocytoma, respectively. The presence of occasional microt ubules and rare primitive presynaptic processes, accompanied by antisy naptophysin immunoreactivity, established the neuronal nature of the c ells in the enhancing region. The nonenhancing region was composed of a moderately cellular neoplasm of fibrillar astrocytes that were mitot ically active. The 5-year-old girl presented with a left parietal lobe neoplasm, which histologically was composed of lobular proliferations of neuroblasts and glia. The neuroblastic populations exhibited evide nce of maturation with small anaplastic cells, spindle-shaped cells, a nd large dysmorphic ganglion cells. The glial tumor showed both well-d ifferentiated fibrillary astrocytes with microcysts and anaplastic pop ulations with central necrosis and pseudopalisading. Conclusions.-Pres ent classification systems devised to describe mixed neuronal and glia l tumors do not adequately encompass the diversity of morphologies pre sented by these two cases. We conclude that the terms cerebral neurobl astoma-anaplastic astrocytoma for case 1 and cerebral ganglioneuroblas toma-glioblastoma for case 2 are preferred because they convey useful clinical information by reflecting concepts already encompassed by the World Health Organization's classification system of tumors of the ce ntral nervous system.