Abstract

Reactive mesothelial cells are frequently found in the smear, of body fludid dffusion when associated with liver cirrhosis, pulmonary tuberculosis, congestive heart failure or pulmonary infarction. But it is not easy to differentiate these reactive mesothelial cells from macrophages or various types of malignant cells. In order to investigate the morphology of hyperplastic mesothelial cells, in comparison with the various types of malignant cells in the effusion, this experiment was designed. The tissue reaction was evoked by intraperitoneal injection of 2.5 ml of 2% Talcum suspension. The results obtained were as follows: 1) On light microscopic observation of the tissure, until 5 days, cytoplasm and nucleus of mesothelial cells became larger and nucleoi became prominent. After then, cytoplasm and nucleus became smaller and at 28 days after injection of Talcum suspension, cellular features became similar to those of normal ones. 2) On cytologic observation of touch print specimens, hyperplastic mesothelial cells became round to oval, and their cytoplasm became conspicuous. Nuclei were vesicular, and nucleoi were prominent. N/C ratio was decreased than normal. 3) On electron microscopic observation, hyperplastic mesothelial cells did not have microvilli, but had a few cytoplasmic globular projections, loosely approximated cellular junctions, larger and more abundant intracytoplaomic vesicles when compared with normal one. Chromatin clumping, irregular thickening of nuclear membrane and prominent nucleoi were also noted.