[Ultrastructural and cytochemical studies of malignant histiocytosis].
The internal and surface ultrastructure and cytochemistry (MPO, AP) of the histiocytes from 16 patients were studied. The results showed that poorly differentiated histiocyte was irregular in cell contour with various projections. All had more or less neoplastic histiocytes in which numerous vacuoles and blisters along peripheral plasma membrane were seen. The neoplastic cells had numerous lysosomes, abundant short strands of rough endoplasmic reticulum, and free and poly-ribosomes in the cytoplasma. Long profiles and ring of RER as well as expansive forms were seen in 4 cases. The mitochondria were generally normal although an occasional elongated form and their cristae showed destroyed architecture in 6 cases. Occasionally, perinuclear bundles of microfilaments and prominent Golgi apparatus were seen. The nuclei of the neoplastic histiocytes were irregularly shaped and most had one or two huge nucleoli. Circular nuclear bodies were often seen. The ultrastructural cytochemistry of the neoplastic histiocytes showed: MPO was weakly positive in about 1/4 to 1/2 of the cells. AP reaction in all of the neoplastic histiocytes was always strongly positive located in the nuclear membrane. RER, lysosomes granules and Golgi apparatus. Under SEM, various surface characteristics of the neoplastic histiocytes were seen such as bleb-covered surface; bleb-ruffled surface, and ruffled surface.
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D000328:Adult; D005260:Female; D006644:Histiocytes / Q000648:ultrastructure*; D054747:Histiocytic Sarcoma / Q000378:metabolism / Q000473:pathology*; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008875:Middle Aged