title: MRI features of intraductal papilloma of the breast: sheep in wolf's clothing?
abstract: BACKGROUND
  Intraductal papillomas often present as small, smooth masses, dilated ducts or microcalcifications at mammography and as smooth, hypoechoic masses at sonography. At magnetic resonance imaging (MRI), intraductal papillomas often present as small smooth masses, however, often with strong enhancement with type 2 or 3 time intensity curves. The result of the MR analysis is therefore not infrequently inconclusive in order to characterize the mass as benign or malignant.
  
  
  OBJECTIVE
  To characterize the appearance of intraductal papillomas of the breast at MRI, and determine whether the application of diagnostic rules described in literature could contribute to correctly classifying the lesions as benign.
  
  
  METHODS
  Twenty patients with histologically proven intraductal papillomas were included. Two radiologists independently reviewed the MR images of the breast. The BI-RADS(®) nomenclature was used to describe morphology and contrast-enhancement kinetics. Interobserver agreement in the interpretation of the MR images by the two investigators was performed. Kappa coefficient was calculated as index for the level of agreement. Subsequently, three sets of diagnostic rules, including the Göttinger score described by Fischer and the interpretation flowcharts according to Kinkel and to Tozaki were applied to characterize whether a biopsy should be recommended or not.
  
  
  RESULTS
  All papillomas presented as masses on dynamic contrast-enhanced MRI. Only five papillomas showed a round, oval, or lobulated shape combined with smooth margins and continuous rise of the time intensity curve. Using the Göttingen score, biopsy would be recommended in 16 patients. Based on the interpretation flowcharts of Kinkel and of Tozaki, an additional 13 and 10 papillomas, respectively, were correctly classified as benign. Dilated ducts were visible in 10 patients. The interobserver agreement was good or excellent for all included variables.
  
  
  CONCLUSIONS
  Including systematic analysis of breast MRI to the diagnostic protocol and interpreting the images according to predetermined diagnostic rules, most solitary intraductal papillomas of the breast may be correctly characterized as benign.
authors.affiliation: Department of Radiology, Stavanger University Hospital, Norway. kurk@sus.no
authors.forename: Kathinka D
authors.initials: KD
authors.lastname: Kurz
authors.forename: Sumit
authors.initials: S
authors.lastname: Roy
authors.forename: Andreas
authors.initials: A
authors.lastname: Saleh
authors.forename: Raihana
authors.initials: R
authors.lastname: Diallo-Danebrock
authors.forename: Per
authors.initials: P
authors.lastname: Skaane
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D003287:Contrast Media / Q000493:pharmacokinetics; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008408:Mastectomy; D008875:Middle Aged; D018300:Papilloma, Intraductal / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA