title: Ultrasonographic features of medullary thyroid carcinoma and their diagnostic values.
abstract: BACKGROUND
  Medullary thyroid carcinoma (MTC) is a rare malignant tumour and usually difficult to diagnose with ultrasound. The aim of the study is to summarize the sonographic features of MTC and evaluate their diagnostic values.
  
  
  METHODS
  We analyzed the sonographic features of 35 MTCs and 50 benign nodules with respect to nodular size, echogenecity, internal content, shape, height/width, border, peripheral halo, calcifications and colour flow pattern. The ratio of long to short axis, echogenecity, internal content and calcifications were also assessed in cervical lymph nodes. The differences in sonographic features between MTCs and benign nodules were analyzed with Chi square test. The diagnostic efficiency of each sonographic feature was determined.
  
  
  RESULTS
  The main sonographic features of MTC were hypoechogenicity (including marked hypoechogenicity) (n = 34, 97%), internal solid content (n = 29, 83%), taller than wide (n = 34, 97%), well defined border (n = 24, 69%), microcalcifications or macrocalcifications (n = 23, 66%). The echogenicity, internal content, shape, peripheral halo and calcifications were significantly different between these two groups, while the tall/wide, border, and perinodular and intranodular vascularisation were not significantly different. Among all the individual sonographic features, irregular shape had the highest diagnostic efficiency with a sensitivity of 51% and specificity of 92%. The combination of marked hypoechogenicity, microcalcifications, and irregular shape yielded a sensitivity of 77% and specificity of 86%.
  
  
  CONCLUSIONS
  The typical sonographic features of MTC are hypoechogenicity, predominantly solid, irregularly shaped with intranodular micro- or macro-calcifications. The combination of multiple sonographic features is helpful, but not definitive, for the diagnosis of MTC.
authors.affiliation: Department of Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Cai
authors.forename: He
authors.initials: H
authors.lastname: Liu
authors.forename: Wen-Bo
authors.initials: WB
authors.lastname: Li
authors.forename: Yun-Shu
authors.initials: YS
authors.lastname: Ouyang
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Xue-Lian
authors.initials: XL
authors.lastname: Wang
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Zhang
authors.forename: Jian-Chu
authors.initials: JC
authors.lastname: Li
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D018278:Carcinoma, Neuroendocrine; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D014463:Ultrasonography; D055815:Young Adult