Ultrastructure of cutaneous granulomas and mononuclear cells from patients with sarcoidosis.

Routine electron microscopy was carried out on biopsy material taken in an active stage from cutaneous sarcoid granulomas of 5 patients. In addition, mononuclear cells isolated from the peripheral blood of 2 patients and 2 controls were studied prior to and after culture with phytohemagglutinin. The infiltrating cells of the sarcoid granulomas varied only slightly from patient to patient. The dominant cell types were macrophages and epithelioid cells rich in endoplasmic reticulum. Epithelioid cells with numerous secondary lysosomes were frequently seen. Typical as well as atypical lymphocytes, giant cells and epithelioid cells with many primary lysosomes were less frequent. No atypical lymphocytes were seen among the mononuclear cells from the peripheral blood, either before or after culture with phytohemagglutinin.