[Bronchioloalveolar carcinoma illustrating difficulties in diagnosis and determination of operative management; report of a case].

A 56-year-old male was admitted to our hospital to treat for an abnormal lung shadow. Computed tomography (CT) revealed the shadow with ground-glass opacity that was 30 mm in diameter at left S6 lesion. Although transbronchial lung biopsy had been performed, histological diagnosis could not be made. We had expected the tumor could not be resected completely with a partial lung resection. Additionally, he refused being done a lower lobectomy without a histological diagnosis. So we performed a S6+S* segmentectomy with No. 7-12 lymph node dissection. Although the intraoperative frozen section diagnosis was an atypical adenomatous hyperplasia, the tumor was finally diagnosed as bronchioloalveolar carcinoma (BAC) because of its nuclear atypia. We did not resect the residual part of left lower lobe because he refused the additional operation and might have histopathologically no residual tumor and lymph node metastasis. At present, he is alive without any evidence of recurrence.