Synchronus presentation of early-stage small cell carcinoma and adenocarcinoma in the same lung lobe

A 73-year-old man with no symptoms was admitted to our hospital with a nodular shadow (>2 cm) in the left upper lung field on chest X-ray. A histological diagnosis (small cell carcinoma) was obtained by bronchoscopic examination including a transbronchial lung biopsy (TBLB). The preoperative clinical staging was T1N0M0 (StageIA). After preoperative chemotherapy (CDDP + CPT11) was carried out, a nodule in the left S(1+2) diminished remarkably, but a smaller nodule in the left S3 (>8 mm) remained unchanged. While the nodule in the left S(1+2) (small cell carcinoma) had become completely necrotic by the time the final diagnosis was made after resection of the left upper lobe, histological diagnosis of the nodule in the left S3 revealed a well differentiated adenocarcinoma. Synchronous presentation of early-stage lung cancer consisting of small cell carcinoma and adenocarcinoma was identified in the same left upper division of the lung. Because there have been the few previous reports regarding cases of synchronous presentation of early-stage lung cancer in the same lung lobe, we also report on the clinical characteristics, thus adding this case to the five previously reported cases.