P2.04-041 Two Cases of Pulmonary Schwannoma: Topic: Esophageal Cancer and Other Malignancies

Abstract

Schwannomas are benign tumors that arise from peripheral, spinal, or cranial nerves. They occur commonly in the head, neck, and flexor surfaces of upper and lower extremities, but rarely in the bronchi or the lungs. We encountered two cases of pulmonary schwannoma treated with surgical resection, and reviewed previous reports on the clinical and pathological features of this disease. Case 1: A 69-year-old woman was admitted to a regional hospital with symptoms of cough and appetite loss. Computed tomography (CT) revealed a tumor in her left lung and obstructive pneumonitis in the left lower lobe. After undergoing treatment for pneumonitis with antibiotics, she was transferred to our hospital for further examination of the tumor. Bronchofiberscopy revealed a polypoid mass with a smooth surface, which near completely occluded the left lower lobe bronchus. Transbronchial biopsy did not provide a definite diagnosis. 18-Fluorodeoxyglucose (FDG) positron emission tomography (PET) detected mild FDG uptake in the tumor (maximum standardized uptake value: 3.2). Because of the resulting clinical suspicion of malignancy in this tumor, the patient underwent surgical treatment. We initially considered left lower lobectomy or left lower sleeve lobectomy as curative surgical procedures, but eventually we performed left pneumonectomy because the tumor was tightly adhered to the upper pulmonary vein. Histopathological examination revealed that the tumor was composed of spindle cells arranged in a fascicular pattern without abnormal mitosis. Immunohistochemical staining demonstrated positive staining in the tumor cells for S-100 protein. On the basis of these findings, the tumor was diagnosed as a bronchial schwannoma. Case 2: A 54-year-old man was referred to our department, because he had an incidental finding of an abnormal shadow in the right lung field. Chest CT examination revealed the presence of a 7 mm, well-defined nodule in the periphery of the right middle lobe. 18-FDG PET did not show significant FDG uptake within the nodule. We could not exclude the possibility of malignancy; therefore, we performed video-assisted thoracoscopic wedge resection of the right middle lobe for diagnosis, as well as, treatment. Intraoperative frozen sections suggested that the tumor was a hamartoma or a spindle cell tumor. Postoperatively, the permanent section was examined, and the diagnosis of pulmonary schwannoma was confirmed. We present two cases of pulmonary schwannoma, which is an extremely rare disease. In both cases, we did not obtain a definite diagnosis before surgery. Surgical treatment should be considered when malignancy cannot be excluded.