Intracytoplasmic Crystalloid Structures in a Malignant Fibrous Histiocytoma: Ultrastructural and Cytochemical Study

Abstract

Crystalloid structures were frequently observed in the cytoplasm of the tumor cells of a malignant fibrous histiocytoma arising in the left leg of a 71-year-old female. These structures were located in the cytoplasm of the fibroblastlike and histiocyte-like tumor cells. The structures consisted of an aggregate of dense granules without unit membrane. Neither glycoproteins nor polysaccharides were detected in these structures on sections stained with chromic acid-phosphotungstic acid or periodic acid-thiocarbohydrazide-silver proteinate. On sections from acrylate-embedded specimens, the structures were easily digested by trypsin and protease but were not sensitive to RNase. Although the significance and origin of these structures remain obscure, the results indicate that the crystalloid structures in the present study are mainly composed of proteinaceous substance.

Electron microscopic evidence of a viral nature for osteoclast inclusions in Paget's disease of bone

“…Since it has been reported that paramyxovirus protein is sensitive to RNase on acrylate embedded sections, our results are in agreement in indicating the presence of ribonucleic acid in the structures (Gyorkey et al 1972;Mii et al 1988). However, we cannot solve the problem of why the structures showed a positive immunocytochemical reaction to two antibodies, and why the reaction was positive in only one case.…”

Malignant peripheral nerve sheath tumour with annulate lamellae mimicking pleomorphic malignant fibrous histiocytoma

“…Other features seen in thecase of Mii et aI. 16 which are also seen in annulate lamellae are the apparent continuity of the lamellae (in some areas) with the rough endoplasmic reticulum and the presence of electron-dense bodies associated with the crystalloids. Dense bodies have been described in association with annulate lamellae and seem to represent nucleolar Differentiation of annulate lamellae appears to result in the dispersal of these dense cytoplasmic masses and the development of extensive rough endoplasmic reticulum and many polyribosomes.I8 This case report illustrates two interesting points: the hitherto undescribed presence of annulate lamellae in a malignant peripheral nerve sheath tumour and another example of a sarcoma with the histological features of pleomorphic MFH exhibiting ultrastructural evidence of Schwann cell differentiation.…”