Ultrastructural evidence for astroglial histogenesis of the monstrocellular astrocytoma (so-called monstrocellular sarcoma of brain)

Five astrocytomas grade III to IV, three fibrosarcomas and two so-called monstrocellular sarcomas were compared by light and electron microscopy in an attempt to determine the histogenesis of the last neoplasm. The bizarre giant cells characteristic of the monstrocellular tumor were found to be quite similar to those of the grade III to IV astrocytomas. Ultrastructural similarities between the monstrocellular tumor and astrocytomas and dissimilarities between these tumors and fibrosarcomas support an astrocytic origin; the authors suggest that these peculiar tumors be called monstrocellular astrocytomas or astrocytoma: monstrocellular variant.