Lupus vulgaris--a case diagnosed more than 20 years after onset.

A 47-year-old Turkish woman developed an erythematous scaly plaque on her thigh over 20 years. Cutaneous sarcoidosis had been diagnosed eight years previously on a skin biopsy. We confirmed Mycobacterium tuberculosis infection by polymerase chain reaction and cultivation of the causative organism from lesional skin. After several months of antituberculous treatment with isoniazid, rifampicin, ethambutol and pyrazinamide, the lesion resolved.