title: Clinicopathologic characteristics of synchronous primary thyroid cancer detected by initial staging 18F-FDG PET-CT examination in patients with underlying malignancy.
abstract: BACKGROUND
  The objective of this study was to define clinicopathologic characteristics in concurrent primary thyroid cancer detected by initial (18)fluorine-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) scanning in patients with underlying malignancy.
  
  
  METHODS
  Among 155 patients with known underlying malignancy and with focal FDG uptake in the thyroid, 25 patients (22 females; mean age ± SD 54.4 ± 11.2 years; age range 27-70 years) who were confirmed as having papillary thyroid cancer (PTC; synchronous thyroid cancer) by cytological examination were included. Another 25 patients (24 females; mean age ± SD, 48.8 ± 12.7 years) with focal uptake in preoperative (18)F-FDG PET-CT due to PTC and no history of other malignancy (primary thyroid cancer) were also included. Immunohistochemical studies were performed for glucose transporter-1 (GLUT-1) and vascular endothelial growth factor (VEGF).
  
  
  RESULTS
  GLUT-1 expression was significantly lower in synchronous thyroid cancer (7 of 25 patients, 28%) compared with primary thyroid carcinoma (15 of 25 patients, 60%; p = 0.045). However, age and tumor size of synchronous thyroid cancer were not significantly different from the patients with primary thyroid carcinomas. There was no significant difference in VEGF expression, maximal standardized uptake values, extrathyroidal extension, lymph node metastasis, advanced stage, and multifocality between both thyroid cancer groups.
  
  
  CONCLUSIONS
  Clinicopathologic characteristics of synchronous thyroid cancer in patients with underlying malignancy were not different from those of patients with primary thyroid cancers except for GLUT-1 expression.
authors.affiliation: 1 Department of Internal Medicine, Pusan National University , Busan, South Korea .
authors.forename: Bo Hyun
authors.initials: BH
authors.lastname: Kim
authors.forename: Chang Hun
authors.initials: CH
authors.lastname: Lee
authors.forename: Seong-Jang
authors.initials: SJ
authors.lastname: Kim
authors.forename: Yun Kyung
authors.initials: YK
authors.lastname: Jeon
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Yong Ki
authors.initials: YK
authors.lastname: Kim
authors.forename: In Ju
authors.initials: IJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging*; D002291:Carcinoma, Papillary; D002648:Child; D005260:Female; D019788:Fluorodeoxyglucose F18; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D055815:Young Adult
chemical_list: D051272:Glucose Transporter Type 1; D019275:Radiopharmaceuticals; C495677:SLC2A1 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D019788:Fluorodeoxyglucose F18