[Tuberculosis cutis luposa gigantea with Mycobacterium bovis detection].
In an 80-year-old woman, retired farmworker, we observed lupus vulgaris extending over more than half of her leg. The extreme size of the affected area made us talk of a giant form in this case. Bacteriological investigation revealed Mycobacterium bovis. The minimal amount of tuberculin required to induce a positive intradermal reaction was 10 IU (GT Behring). Another case with similar dimensions (reported by Christiansen in 1967) had been caused by Mycobacterium avium and developed over a period of at least 5 years. The vast cutaneous affection of our patient, in contrast, had developed within only one year, starting from a brownish macula of the size of a palm on her upper leg. This macula - presumably the manifestation of quiescent lupus vulgaris - had not changed for more than 40 years. This late exacerbation of post-primary tuberculosis might have been favored by the patient's reduced immunologic resistance on account of her advanced age. In addition, local cofactors - namely ankylosis of her knee and contact eczematous dermatitis - have to be considered. In accordance with the resistogram, the disease responded to monotherapy with isoniazide.