title: MR features to suggest microinvasive ductal carcinoma of the breast: can it be differentiated from pure DCIS?
abstract: BACKGROUND
  Morphologic and kinetic characteristics of breast lesions are regarded as a major criterion for their differential diagnosis in dynamic magnetic resonance imaging (MRI). However, there have not been well-reported MRI findings of microinvasive ductal carcinoma.
  
  
  OBJECTIVE
  To evaluate MRI characteristics of microinvasive ductal carcinoma of the breast and to compare MRI findings in patients with microinvasive ductal carcinoma and pure ductal carcinoma in situ (DCIS).
  
  
  METHODS
  Eighty-one patients with pathologically confirmed microinvasive ductal carcinomas (n = 37) or pure DCIS (n = 44) were included in this study. The MRI findings were analyzed without knowledge of the pathologic and conventional imaging findings. For all the lesions detected on MRI, morphologic and kinetic analyses were performed according to the Breast Imaging Reporting and Data System. For the non-mass lesions, the presence of clustered ring enhancement was also analyzed. Statistical analyses were performed using Student's t test, χ(2) test, and Fisher's exact test.
  
  
  RESULTS
  In total 35 cases of microinvasive ductal carcinoma and 39 cases of DCIS were detected on MRI. The most common and dominant MRI findings of microinvasive ductal carcinoma and DCIS were non-mass lesions with heterogeneous enhancement. However, the spiculated margin of the mass-type lesion (P = 0.022), the segmental distribution (P = 0.023), and clustered ring enhancement (P = 0.006) of the non-mass-type lesion, and the enhancement kinetics showing strong initial enhancement (P = 0.004) with subsequent wash-out (P = 0.001) were significantly more frequent in microinvasive ductal carcinoma than in DCIS.
  
  
  CONCLUSIONS
  Non-mass lesions with segmental distribution, heterogeneous enhancement, and strong initial enhancement with a wash-out curve were the dominant MRI findings of microinvasive ductal carcinoma. Compared with DCIS, microinvasive ductal carcinoma showed more suspicious imaging characteristics. For the non-mass lesions, clustered ring enhancement was also a characteristic finding of microinvasion on MRI.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul.
authors.forename: Soo Yeon
authors.initials: SY
authors.lastname: Hahn
authors.forename: Boo-Kyung
authors.initials: BK
authors.lastname: Han
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Ko
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Shin
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Hwang
authors.forename: Meeyoung
authors.initials: M
authors.lastname: Nam
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016009:Chi-Square Distribution; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008197:Lymph Node Excision; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012189:Retrospective Studies; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: Breast; MR imaging; ductal carcinoma in situ; microinvasion; neoplasms – primary