Intralobar sequestration with tuberculous infection confined to the sequestrated lung

A 22-year-old female was referred to the hospital suffering from a persistent, non-productive cough and repeated exacerbations of a right lower zone infiltrate suggestive of pulmonary sequestration. Angiography revealed an aberrant artery that originated from the left side of the descending aorta, crossed the aorta anteriorly, flowed through the right lower lobe and drained into the right inferior pulmonary vein. Right lower lobectomy was conducted by open thoracotomy. Gross examination revealed mucoid impaction of bronchi in the sequestration. Microscopy demonstrated a clear boundary between sequestrated and normal lung, as well as caseating epitheloid granulomas confined to the sequestration. As the aberrant artery fed both sequestrated and adjacent normal lung and the boundary did not involve the pleura, the lesion was classified as a Pryce's type II intralobar sequestration. No acid-fast bacilli were observed, but homogenates of the sequestration were positive for Mycobacterium tuberculosis by polymerase chain reaction. The patient was treated with isoniazid and rifampicin daily for 9 months, and 6 years later her clinical status remained excellent. Tuberculosis confined to a sequestration is extremely rare and characteristics of the aberrant artery suggested this intralobar sequestration was likely to be congenital in origin.