抄録
Three cases of sarcoidosis were reported with electron microscopic observation on cells constituting the granuloma in the lymph nodes. In two of these three cases, simultaneous enzyme histochemical study was performed.
Interesting facts revealed by the present study were as follows.
1) Epithelioid ceps constituting the granuloma of sarcoidosis resemble reticulum cells or monocytes. They demonstrate prominent cytoplasmic processes interdigitating with juxtaposed similar cells. Occasionally, tight junction develops between these interdigitations. Invagination of such compelx membrane structure with tight junction was seen in one of the multinucleated giant cells.
2) Multinucleated giant cells have a large number of lysosomes of moderate to minute size. In other respects, they are quite similar to epithelioid cells. Cytoplasmic membrane also forms prominent processes.
3) Between epithelioid cells are fibroblasts, lymphocytes and occasional plasma cells. Fibroblasts are more frequent in the peripheral portion of and around the granuloma. Characteristic hyalinization of this disease probably is due to prominent activity of f ibroblasts rather than due to immunological processes.
4) Enzyme histochemical study revealed prominent acid phosphapatase and glucosaminidase activity in the giant cells and also in some of the epithelioid cells. This finding corresponds well to the ultrastractural feature. These lysosomal enzyme activity are quite similar to that of tuberculosis granuloma and may be related to the digestion of possible causative micro-organisms.
5) During the present investigation, however, no microorganisms or structures suggestive of such, including viruses, are encountered in the granuloma of sarcoidosis.
