[Atypical erythema induratum Bazin with tuberculous osteomyelitis].

Diagnosis of all types of cutaneous tuberculosis is challenging because the clinical picture of these diseases is highly variable. We describe the case of a 79-year old woman with an atypical presentation of Erythema induratum Bazin (EIB) on the chest and left arm in association with a tuberculous osteomyelitis of the left olecranon. Surprisingly, M. tuberculosis grew also from biopsies of the EIB-lesions. This contradicts the conventional view that considers EIB (a tuberculid) to be caused by a hypersensitivity reaction to mycobacteria. The presented case supports the hypothesis that EIB may also be caused by hematogenous or lymphatic spread of viable M. tuberculosis.