Primary pulmonary mucinous adenocarcinoma in a young adult with MELAS syndrome

Abstract

A 25-year-old man with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome presented with an abnormal shadow in the right middle lung area on a chest radiograph. Chest computed tomography images revealed a 30-mm partially solid tumor in segment 4 of the right middle lung. There were no signs of lymph node nor distant metastases. The tumor was suspected to be lung adenocarcinoma based on bronchoscopy. We performed a right middle lobectomy with dissection of the hilar and mediastinal lymph nodes (ND2a-2). We were concerned about lactic acidosis due to mitochondrial abnormalities. Therefore, we used a bicarbonate Ringer solution and normal saline not containing lactate. No signs of convulsions, myopathy, or acute respiratory failure were noted during the perioperative period, and the patient was discharged from the hospital 6 days after surgery. The postoperative diagnosis was primary pulmonary mucinous adenocarcinoma (pT1cN0M0, p-StageIA3). Even in young patients presenting with pulmonary nodules, the differential diagnosis should include lung cancer. In addition, it is necessary to pay close attention to the prevention of complications when performing operative management of MELAS patients.