Cutaneous sarcoidal reaction in a patient with pulmonary tuberculosis.

: Sarcoidosis is a systemic disorder characterized by non-caseating epithelioid granulomas that may affect any organ system. The etiology of sarcoidosis is unknown, but several immune aberrations are thought to play a role in its pathogenesis. The possible role of mycobacterial infection in the pathogenesis of sarcoidosis has been suggested. In recent studies mycobacterial DNA was detected in lung tissues and bronchial lavage fluid of 30% to 50% of patients with sarcoidosis. We report a patient with pulmonary tuberculosis treated successfully three years earlier who developed cutaneous sarcoidosis with negative polymerase chain reaction (PCR) assay for mycobacterial DNA of the skin lesion.