A woman in her 50s presented with a 2-year history of a large, shallow ulcer of the scalp. It began as a small sore and gradually enlarged to 10 to 12 cm to cover much of the midscalp and vertex (Figure). The ulcer surface had a thick, yellow, foul-smelling adherent crust, and the edges of the ulcer were marked by violaceous erythema and hyperpigmentation. Examination was also notable for an annular, violaceous, atrophic, scaly 3-cm plaque on the right anterior forehead. She had no significant cutaneous lesions elsewhere. Biopsy of the scalp revealed multiple areas of granulomatous inflammation in the dermis, characterized by nodular aggregates of epithelioid histiocytes, multinucleated giant cells with asteroid bodies, and a surrounding lymphoplasmacytic infiltrate, which were most consistent with sarcoidosis.