A case of scar sarcoidosis developing in an old scar area on the forehead.

Sarcoidosis is a multisystem disease characterized by noncaseating granuloma development. Scar sarcoidosis is a rare cutaneous form of sarcoidosis developing on previous cutaneous scar areas. The lesions may be solitary or occur along with systemic disease. We present the case of a female patient that developed cutaneous sarcoidosis in an old scar area on the forehead that was acquired 30 years ago due to injuries from a fall. Histopathological examinations of the excisional scar biopsy revealed non-necrotizing, noncaseating granulomatous inflammatory structures comprised of epithelioid cells and Langhans giant cells with lymphocytic infiltration within the reticular dermis consistent with sarcoidosis. High-resolution CT revealed bilateral mediastinal lymphadenopathy. Patients with inflammatory skin lesions at the sites of preexisting scars should be investigated for sarcoidosis. Histopathological examination of skin biopsy specimens usually provides the correct and final diagnosis.