[Therapy-resistant "psoriasis vulgaris"].

A 61-year-old patient had a 25-year history of erythematous scaling lesions, diagnosed and treated as psoriasis vulgaris. He presented with a growing nodule within the erythematous plaque. Biopsy shows epithelioid cell granulomas with prominent Langhans giant cells. There was no sign of a squamous cell carcinoma. The tuberculin test was strongly positive and M. tuberculosis complex was detected in the biopsy material by PCR. He was diagnosed with lupus vulgaris, the most frequent form of cutaneous tuberculosis. Other types include tuberculosis verrucosa cutis, tuberculosis cutis orificialis and disseminated military tuberculosis. The patient was treated with rifampicin, isoniazid, pyrazinamide and ethambutol for two months, following a four month treatment with rifampicin and isoniazid. The skin lesions rapidly resolved under antituberculotic treatment.