Perforating Plaque-Type Pretibial Sarcoidosis With Granulomatous Phlebitis.

To the Editor: An 80-year-old woman presented with a 3-year history of asymptomatic lesions of the lower extremities. Physical examination showed well-circumscribed infiltrated erythematous to yellow plaques with slightly elevated borders involving pretibial skin (Fig. 1A). Histological examination revealed multiple noncaseating epithelioid granulomas with multinucleated giant cells in the dermis (Fig. 1B), accompanied by a mild lymphocytic infiltrate. There were nests of histiocytes in the epidermis, with focal epidermal thinning and an overlying mound of parakeratosis, suggesting transepidermal elimination/ perforation (Fig. 1C). Muscular vein at the dermal–subcutaneous junction was surrounded by multinucleated giant cells with associated partial destruction of the muscular layer (Fig. 2A). Elastica van Gieson staining confirmed that the involved vessel was a vein and highlighted disruption, fragmentation, and loss of the elastic lamina in the areas infiltrated by sarcoidal granulomas (Figs. 2B, C). Dermal mucin deposition was not detected. Liver and kidney functions were normal, and blood glucose levels were within normal ranges. Angiotensinconverting enzyme and soluble IL-2 receptor serum levels were normal, and neither PR3-antineutrophil cytoplasmic antibody nor MPO-antineutrophil cytoplasmic antibody was detected. Computed tomography showed small nodular shadows and mediastinal lymphadenopathy. Ophthalmological examination revealed uveitis. Ulcers developed within the plaques, which were improved by application of topical alprostadil alfadex ointment. We diagnosed this patient’s cutaneous lesions on the lower extremities as plaque-type sarcoidosis. Necrobiosis lipoidica (NL) should be included in the differential diagnosis because NL is a granulomatous dermatosis commonly FIGURE 1. A, Well-circumscribed erythematous plaques with mild scales and slightly elevated erythema at the periphery of the lower leg. B, Histological features showing noncaseating epithelioid cell granulomas with lymphocyte infiltration in the dermis (·40). C, Sarcoid granuloma within the epidermis, along with parakeratosis in the overlying stratum corneum (·400). Transepidermal elimination of sarcoidal granulomas is indicated by arrows.