A very rare case of benign notochordal cell tumor of the lung

Abstract

An abnormal lung shadow was detected in a 35-year-old man during a physical examination, and he was followed-up carefully at a nearby hospital. Since the abnormal lung shadow had slightly enlarged after 4 years, the patient was referred to our hospital for further examination. Chest computed tomography revealed a 5-mm well-circumscribed nodular shadow in the right upper lobe of the lung. A benign tumor such as hamartoma was suspected preoperatively; partial resection of the right upper lobe with video-assisted thoracoscopic surgery was performed for both diagnosis and treatment. The intraoperative diagnosis was a myxoid tumor, very rare as a lung tumor, and it was difficult to diagnose as benign or malignant. Histologically, it was identified as an extra osseous benign notochordal cell tumor, based on tumor cells lying in a sheet-like arrangement, immunopositivity for brachyury, and lack of both nuclear atypia and a lobulated structure. Systemic screening performed postoperatively revealed no suspected primary lesion, and the tumor was diagnosed as a benign notochordal cell tumor of the lung.

This is a very rare case; the fifth case report of benign notochordal cell tumor of the lung. The post-operative course was uneventful and there had been no recurrence as of 6 months after surgery.