Epidermal changes in cutaneous lesions of sarcoidosis

The essential histologic finding of cutaneous sarcoidosis is a noncaseating epithelioid cell granuloma in the dermis or, infrequently, in the subcutaneous tissues. However, there have been cases of cutaneous sarcoidosis with clinical appearances altered by epidermal changes such as ulcers, the formation of psoriasiform or verrucous plaques, and by hypopigmentation. In this study, histologic examinations of the epidermis were performed in cutaneous lesions of 62 cases of sarcoidosis. Seventy-nine percent (49/62) showed epidermal changes including hyperkeratosis (8/49), parakeratosis (10/49), acanthosis (6/49), and epidermal atrophy (35/49). Lymphoid cells extended into the epidermis in 50 of 62 cases. The infiltration patterns were in the forms of a spongiotic reaction (21/50), lichenoid tissue reaction (9/50), and simple exocytosis without epidermal vesiculation (20/50). Immunohistochemical studies showed that the lymphoid cells in the epidermis expressed CD3, 8, 45RO, and 11a. The epidermal changes overlying the granulomatous lesions contribute to the variety of clinical manifestations and are in part associated with the pathogenesis of cutaneous sarcoidosis.