Diehl Michaela, Graichen Sinikka, Menzel Christian, Lindhorst Elmar, Grünwald Frank
Department of Nuclear Medicine, Hospital of Johann Wolfgang Goethe University, Frankfurt, Germany.
Clin Nucl Med. 2003 Sep;28(9):728-31. doi: 10.1097/01.rlu.0000082658.78218.0f.
Insular thyroid cancer (ITC) is known to be a rare subtype of follicular thyroid carcinoma showing poor differentiation and an unfavorable prognosis. The authors evaluated the use of F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) for restaging and follow-up in ITC.
Five patients (2 male, 3 female) with elevated thyroglobulin levels (mean, 86 ng/mL; range 1.3-180 ng/mL) during follow-up underwent FDG PET (Siemens ECAT Exact 47). PET results were correlated to histopathologic and radiologic findings as well as to the results of whole-body radioiodine scintigraphy. In 1 patient a series of 4 PET scans was done.
FDG PET showed a total of 10 tumor sites, at least 1 in each patient. Four of those lesions were detected by computed tomography (CT) as well, which in addition revealed 3 lesions that had normal glucose consumption. Five PET lesions were missed by the CT scan because they were found outside the examined volume of CT. Only 1 PET-positive lesion was also radioiodine positive. Three radioiodine-positive lesions with normal glucose metabolism were detected.
As known for well and poorly differentiated thyroid cancer of the follicular epithelium, ITC may also show discordance between radioiodine studies and FDG-positive lesions. Given their initially poor differentiation, the ITC clearly showed the expected dominance of less well-differentiated, FDG-positive lesions. Therefore, FDG PET seems to be a very useful tool for the staging and restaging of such tumors.
甲状腺内癌（ITC）是一种罕见的滤泡状甲状腺癌亚型，分化差且预后不良。作者评估了F-18-氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）在ITC再分期及随访中的应用。
5例（2例男性，3例女性）随访期间甲状腺球蛋白水平升高（平均86 ng/mL；范围1.3 - 180 ng/mL）的患者接受了FDG PET检查（西门子ECAT Exact 47）。PET结果与组织病理学、放射学检查结果以及全身放射性碘闪烁扫描结果进行了相关性分析。1例患者进行了4次PET扫描。
FDG PET共显示10个肿瘤部位，每位患者至少有1个。其中4个病灶也被计算机断层扫描（CT）检测到，CT还发现了3个葡萄糖摄取正常的病灶。5个PET病灶因位于CT检查范围之外而未被CT扫描发现。仅1个PET阳性病灶同时也是放射性碘阳性。检测到3个放射性碘阳性但葡萄糖代谢正常的病灶。
正如滤泡上皮性甲状腺癌的高分化和低分化情况一样，ITC在放射性碘检查和FDG阳性病灶之间也可能存在不一致。鉴于其最初分化较差，ITC明显表现出低分化、FDG阳性病灶的预期优势。因此，FDG PET似乎是此类肿瘤分期和再分期的非常有用的工具。
