Thymus tuberculosis poorly responding to anti-mycobacterial therapy in a young girl with primary infection.

Tuberculous infection of the thymus is a rare condition, previously described only in young adults. A case of a young girl with primary pulmonary tuberculosis, hilar and mediastinal lymph node enlargement and a partially necrotic mass in antero-superior mediastinum is described. Treatment with three anti-mycobacterial drugs was started, effective in markedly reducing all the intrathoracic abnormalities with the exception of the antero-superior mediastinal mass. Since the radiographic and ultrasonographic appearance of the thymus tuberculous infection may be indistinguishable from other serious conditions, including lymphoma and thymoma, a diagnostic procedure was performed. Evaluation of the resected specimen showed foci of caseation and multiple granulomas with extensive central necrosis within the thymic tissue.