Sugiura Yasoo, Kawamura Masafumi, Nemoto Etsuo, Kaseda Shizuka
Department of Pulmonary and Thoracic Surgery, National Hospital Organization, Kanagawa Hospital, Hadano, Japan.
Kyobu Geka. 2013 May;66(5):387-90.
A seventies year-old woman underwent thymo-thymectomy through a median sternotomy for type B2 thymoma. Annual screening with fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography( CT) did not show any abnormality until 3 years after surgery, when a FDG-positive lesion, 1.5 cm in diameter, was found in the top of the anterior mediastinum. The lesion was resected under the diagnosis of thymoma recurrence, but was pathologically diagnosed as a foreign body granuloma including a suture thread. False-positive results with FDG-PET are related to FDG-uptake by inflammatory cells (e.g. macrophages and lymphocytes in the granuloma). Although FDG-PET is useful for diagnosing the postoperative recurrence of tumors, it should be noted that a foreign body granuloma and local recurrence of tumor have similar growth rates and both appear positive on FDGPET.
一名70岁女性因B2型胸腺瘤经正中胸骨切开术接受胸腺切除术。术后每年进行氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）和计算机断层扫描（CT）检查，直至术后3年均未发现任何异常，此时在前纵隔顶部发现一个直径1.5厘米的FDG阳性病变。该病变在诊断为胸腺瘤复发后进行了切除，但病理诊断为包括缝线在内的异物肉芽肿。FDG-PET的假阳性结果与炎症细胞（如肉芽肿中的巨噬细胞和淋巴细胞）摄取FDG有关。虽然FDG-PET有助于诊断肿瘤术后复发，但应注意异物肉芽肿和肿瘤局部复发具有相似的生长速度，且在FDG-PET上均呈阳性。
