[An adult case of hypoplasia of the left lung disclosed by pneumonectomy for pulmonary M. avium complex infection associated with intractable pneumothorax].

A case of W-P-W syndrome complicated with pulmonary hypoplasia disclosed by pneumonectomy for pulmonary Mycobacterium avium complex infection associated with intractable pneumothorax was reported. A male patient aged 52 years consulted our clinic with chief complaints of cough and abnormal shadows on his chest radiogram, which was consistent with mycobacteriosis on his left lung. MAC infection was soon confirmed by sputum examination and he was treated with RFP, EB, INH combined with CAM. In spite of the chemotherapy, sputum examination of the patient remained positive. Furthermore, eleven months after initiating the treatment, an intractable pneumothorax concurrent with a large dead space at the left lower lung field was consistently observed on his chest radiogram. Therefore, he was first treated by video assisted thoracoscopic surgery, but soon relapsed which led to tention pneumothorax gradually. Consequently, a left pneumonectomy had to be performed and the following developmental abnormalities combined with pathological changes caused by MAC infection were disclosed: concerning the upper lobe, defect of lingula, formation of a peripheral type of congenital air-filled parenchymal cyst measuring 5 x 6 cm in S3, and atelectatic induration caused by MAC infection on the remaining part of the upper lobe where strong adhesion was seen between the chest wall and the lung. Concerning the lower lobe, congenital shortening of visceral pleura, mainly mediastinal surface, causing marked deformity of the lower lobe with elevation of margo inferior. This created a large dead space between the lower lobe and diaphragma, and formation of a walnut-sized nest of atelectatic induration caused by MAC infection in S6. The patient's post-operative clinical course was uneventful and his arterial blood gas was elevated from 76 torr to 99.2 torr. He was discharged three weeks after the operation. Several controversial issues relating to this case were discussed; the predisposition existing on the hypoplastic lung to MAC infection, the possible reason why the congenital pulmonary cyst was not involved in MAC infection, the location of perforation of the upper lobe that caused intractable pneumothorax, and the difficulty in diagnosing congenital air-filled bullous parenchymal cyst by current conventional chest radiogram.