2024 Volume 38 Issue 2 Pages 145-151
A 57-year-old woman was admitted because of bloody septum persisting for 2 weeks. Computed tomography (CT) revealed a 25-mm, well-demarcated, solid nodule in the left lower lobe (S6). She was transferred to our department for surgery and underwent thoracoscopic S6 segmentectomy. Rapid intraoperative cytological diagnosis revealed spindle-shaped cell proliferation. A malignant disease such as a carcinoid, small cell carcinoma, or sarcoma was suspected. In addition, we performed left lower lobectomy and lymph node dissection. Hematoxylin and eosin (HE) staining revealed small, round, neoplastic cells and localized areas of spindle-cell-type tumor cells around the small cells. Therefore, histopathologically undifferentiated carcinoma and high-grade sarcoma needed to be differentiated. Immunohistochemistry indicated that these tumor cells were negative for epithelial markers; therefore, cancer was ruled out. The SYT-SSXI fusion gene was expressed; thus, the definite diagnosis was poorly differentiated type synovial sarcoma. Pneumonia and pulmonary embolism occurred postoperatively, but she recovered well. She was discharged on the 14th postoperative day. Magnetic resonance imaging and positron emission tomography-CT were conducted to detect the primary lesion, but no tumor lesion was found. Therefore, primary pulmonary synovial sarcoma was considered. She has experienced no recurrence for 2 years and 6 months since surgery.
