Tuberculosis remains the major cause of morbidity and mortality by a single infectious agent, particularly in developing countries as Madagascar but isolated
mediastinal tuberculosis (MTB) in the pseudotumor shape has not been described in adults immunocompetent. This form is unusual with the incidence of 0.25%-5.8%. It
occurs most commonly in black people, and presents a differential diagnostic problem. We report a case of a young adult man immunocompetent from Madagascar affected by mediastinal mass. Diagnosis of tuberculosis was made on further biopsy by mediatinostomy and confirmed with histopathology. This case report emphasizes the importance of biopsied tissue culture for routine
bacteriological examination when encountering a mediastinal mass.