RESUMO
Pyomyositis is a muscular infection that is frequently due to commonplace bacteria particularly in immunocompetent patients. However, infections with specific germs can arise even without preliminary risk factors. We report the case of a young non-immunosuppressed patient, who has a sub acute painful tumefaction of a thigh without infectious signs. The clinical examination was in favour of thigh collection. The MRI confirmed this hypothesis and showed an associated osteo-arthritis of the knee. The pus microbiological examination was postitive for Mycobacterium tuberculosis. She favourably evolved under antituberculous treatment and surgical drainage of the collection. As tuberculosis is endemic in our country, we should always consider this diagnosis even in young patients without predisposing factors