An Unusual Acid-Fast Infection of the Knee with Subcutaneous, Abscess-Like Lesions of the Gluteal Region

Abstract

Human infection with acid-fast bacilli other than the usual human, bovine and avian tubercie bacilli aad the lepra bacillus is not commoa. In the past, the tendency to diagnose as tuberculosis all lesions in which there were demonstrable acid-fast bacilli and/or a tissue picture suggesting tuberculosis was very strong. In recent years, however, it has been demonstrated that acid-fast bacilli, clearly not the commonly accepted tubercle bacilli, may produce human infection. Such lesions present to the pathologist a problem in diagnosis since they resemble tuberculosis histologically. Bactcriologicnlly, however, the organisms isolated from such cases vary distinctly from the tubercle bacilli, culturally, although simulating them closely in tissue. In addition, lesions produced by these 'pseudo- tubercle' bacilli usually follow trauma, remain fairly well localized, show little or no tendency to produce progressive disease, and invariably clear up in a period of approximately six mouths to two years with or without treatment. We are reporting in this paper such a case of human infection with an unusual history of 48 years from the time the traumatic infection was contracted to the time diagnosis was finally established. Because the causative agent is considered to be a new and hitherto undescribed species of mycobactcrium, the reporting of the case and a study of the organism is deemed advisable.