title: Invasive lobular carcinoma of the breast: MRI pathological correlation following bilateral total mastectomy.
abstract: BACKGROUND
  Invasive lobular carcinoma (ILC) is more often multifocal and bilateral than invasive ductal carcinoma. MRI is usually recommended for detection of all ILC sites. The performance of known diagnostic breast MRI criteria for ILC characterization has not been evaluated to date using bilateral mastectomy specimens as gold standard.
  
  
  OBJECTIVE
  To determine the value of BI-RADS 2006 MRI criteria for ILC detection and characterization, using pathological examination of bilateral mastectomy specimens as the reference standard.
  
  
  METHODS
  Between 2004 and 2007, we retrospectively included all patients with pathologically documented ILC referred to our institution for bilateral mastectomy and preoperative bilateral breast MRI. The location, diameter, and characteristics (BI-RADS) of all lesions were compared with pathological findings. The sensitivity and positive predictive value of bilateral breast MRI for the diagnosis of ILC were calculated. Association of MRI BI-RADS categorical variables and characterization of ILC were assessed (Fisher exact test).
  
  
  RESULTS
  Among 360 patients treated for ILC in 2004-2007, 15 patients qualified for this study. Thirty-one ILC foci were found on pathological examination (30 ipsilateral and 1 contralateral tumor; mean diameter 23 mm; range 2-60 mm) and all were identified on MRI, with 90% of masses and 10% non-mass-like enhancements; MRI features significantly associated with ILC included absence of smooth margins (P = 0.02) and rim-shaped enhancement (P = 0.039). Enhancement kinetics of the 31 foci were evenly distributed among wash-out, plateau, and persistent profiles. Eleven additional lesions were seen on MRI, mainly corresponding to fibrocystic disease; 91% presented as masses and 9% had a wash-out profile.
  
  
  CONCLUSIONS
  Based on the 2006 BI-RADS criteria, breast MRI shows a high sensitivity for ILC detection, at the expense of a 26% false-positive rate, suggesting that a pathological proof by US- or MR-guided biopsy is required in case of suspicious MRI images in this context.
authors.affiliation: AP-HP, Groupe Henri Mondor Albert Chenevier, Imagerie Medicale, Creteil, France. alain.luciani@hmn.aphp.fr
authors.forename: Aude
authors.initials: A
authors.lastname: Stivalet
authors.forename: Alain
authors.initials: A
authors.lastname: Luciani
authors.forename: Frederic
authors.initials: F
authors.lastname: Pigneur
authors.forename: Thu Ha
authors.initials: TH
authors.lastname: Dao
authors.forename: Pauline
authors.initials: P
authors.lastname: Beaussart
authors.forename: Zahira
authors.initials: Z
authors.lastname: Merabet
authors.forename: Julie
authors.initials: J
authors.lastname: Perlbarg
authors.forename: Evelyne
authors.initials: E
authors.lastname: Meyblum
authors.forename: Laurence
authors.initials: L
authors.lastname: Baranes
authors.forename: Elie
authors.initials: E
authors.lastname: Calitchi
authors.forename: Christophe
authors.initials: C
authors.lastname: Lepage
authors.forename: Yazid
authors.initials: Y
authors.lastname: Belkacemi
authors.forename: Jean-Leon
authors.initials: JL
authors.lastname: Lagrange
authors.forename: Laurent
authors.initials: L
authors.lastname: Lantieri
authors.forename: Alain
authors.initials: A
authors.lastname: Rahmouni
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D018275:Carcinoma, Lobular / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D003131:Combined Modality Therapy; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D016462:Mammaplasty; D008327:Mammography; D015413:Mastectomy, Simple; D008536:Meglumine; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine