2016 Volume 56 Issue 5 Pages 368-372
Background. Primary lung cancers commonly invade the lung parenchyma and, on reaching the visceral pleura, cause pleural dissemination. We herein report a surgical case of primary lung cancer which showed a unique growth pattern of spreading predominantly within the interlobular pleura. Case. A 65-year-old male patient was referred to our department because of an abnormal shadow in the right middle lung field detected on chest X-ray film during the follow-up period of angina. Contrast-enhanced computed tomography revealed slightly enhanced nodule shadows with a beaded appearance in the right minor and major fissures. During the observation period, the size of this abnormal shadow increased slowly with no evidence of lymph node enlargement or distant metastasis. Therefore, the patient underwent surgical resection (right upper and middle lobectomy with partial resection of the right lower lobe) for diagnostic and therapeutic purposes, and lymph node dissection was performed. On a histopathological examination, the tumor was found to be located only partly within the lung parenchyma of the upper lobe but predominantly within the interlobular pleura. The tumor cells were arranged in a tubular or papillary pattern, and immunohistochemical examinations revealed the tumor cells to be positive for TTF-1 and SP-A, leading to a diagnosis of primary pulmonary adenocarcinoma (pT3N0M0). In addition, EML4-ALK translocation was positive, whereas EGFR mutation was negative. The patient received adjuvant chemotherapy with the oral administration of UFT for two years after surgery with no evidence of recurrence. Conclusion. The invasive growth of primary lung cancer within the interlobular pleura is a rare form of progression. In our present case, it was difficult to distinguish between primary lung cancer and other lesions of pleural origin.
