Crystals in an oligodendroglioma: an optical, histochemical, and ultrastructural study

The report describes an oligodendroglioma that was examined in four biopsies and contained a large number of intracytoplasmic crystals. The crystals appeared in neoplastic cells with eosinophilic cytoplasms and eccentric nuclei. They were positive to periodic acid-Schiff stain and resistant to diastase. A lysosomal genesis of the crystals is proposed on the basis of a transition observed between lysosomal bodies with lipid droplets and those with crystalloid electron-dense structures. The morphologic and histochemical features of these crystals are compared to those in other tumors, lesions, and nonneoplastic cells.