ERYTHEMA INDURATUM OF BAZIN - A CLINICOPATHOLOGICAL STUDY OF 20 CASESAND DETECTION OF MYCOBACTERIUM-TUBERCULOSIS DNA IN SKIN-LESIONS BY POLYMERASE CHAIN-REACTION

Erythema induratum of Bazin (EIB) is a chronic, recurring panniculitis that is found predominantly on the legs of women with tuberculin hype rsensitivity. A causal relationship between EIB and Mycobacterium tube rculosis remains elusive because of the absence of demonstrable organi sms in skin lesions. We reviewed the clinicopathological features of 2 0 patients (all women) with positive Mantoux tests (1:10,000 dilution) and characteristic skin lesions of EIB that cleared up with combined antituberculous treatment. Histological examination of skin lesions co nfirmed panniculitis with varying combinations of granulomatous inflam mation, primary vasculitis, and necrosis. Sections from 20 formalin-fi xed, paraffin-embedded skin biopsies obtained from the 20 patients wer e submitted for polymerase chain reaction (PCR) using oligonucleotide primers for the detection of a 123-bp DNA fragment specific for the M. tuberculosis complex. M. tuberculosis DNA was identified in five of t he 20 biopsies. Meticulous care was taken to prevent contamination as a source of false-positive results. Mycobacterial DNA was absent in al l negative controls and in normal skin biopsies from purified protein derivative-positive patients with and without EIB. These results provi de direct evidence that mycobacterial components are present in EIB le sions and strongly suggest that M. tuberculosis is involved in the pat hogenesis of EIB.