The natural history of the sarcoid granuloma.

In the many papers on sarcoidosis, little attention has been paid to the earliest phase of development of the characteristic lesions of this disease. Most authors, like Pautrierl and Ricker and Clark,2 believed that the aggregate of epithelioid cells is the earliest recognizable lesion. An earlier phase characterized by perivascular inflammatory reaction has been claimed by Kissmeyer,3 described in the skin by Kyrle4 and Lever and Freiman,5 and in the heart by Johnson and Jason.6 Little has been written about the significance of the granuloma in the natural history of sarcoidosis or the fundamental question whether the aggregates represent clumping of cells or the results of cell division. Furthermore, do the epitheioid cells represent a slow progressive reaction to some foreign body or are they sequelae of an acute exudative process? To investigate these points, a study was made of the cases of sarcoidosis in the necropsy files of the Banting Institute. Several cases were rejected because the lesions were open to question or because the picture was confused by coincident disease such as disseminated lupus and widespread deposits of a seminoma. There remained 24 cases suitable for this study. A full description of the distribution of the lesions in this series of cases is being published separately. Use was made also of biopsy material obtained through Dr. W. L. Robinson from the Department of Surgical Pathology.