Primary tuberculous myositis: a rare clinical entity.

Summary: Primary tuberculous myositis without underlying pathology has been sparingly reported in medical literature. We report a case of primary tuberculous myositis of left upper arm in a seven-year-old boy. He presented with gradually increasing swelling on the medial aspect of the left arm. Ziehl Neelsen staining of pus collected revealed acid fast bacilli morphologically resembling Mycobacterium tuberculosis and the same was grown on the culture. Histopathological findings were consistent with tuberculosis. The results were confirmed by Genotype MTBDRpluse line probe assay. He was treated with standard four-drug regimen to which he responded well with complete resolution of the lesion.