title: Benign (BI-RADS 2) lesions in breast MRI.
abstract: OBJECTIVE
  To assess the frequency of malignancy in lesions characterized as benign [Breast Imaging-Reporting and Data System (BI-RADS) 2] on breast MRI.
  
  
  METHODS
  In this institutional review board-approved retrospective single-centre study, 1265 consecutive patients (mean age 50 ± 13 years), undergoing dynamic contrast-enhanced MRI (1.5 T) of the breast during a 6 year time period, were eligible. This study investigated the MRI characteristics and frequency of malignancy in 192 of these patients with breast lesions classified as BI-RADS 2. Examinations were read during clinical practice and classified according to the MRI BI-RADS lexicon. Based on the patient's and referring physician's preferences, lesions were either histopathologically verified or were subjected to both clinical and imaging follow-up of at least 2 years (range 2-9 years). Descriptive statistical metrics were calculated.
  
  
  RESULTS
  According to the standard of reference, 0 of 192 (0%) lesions classified as BI-RADS 2 were malignant. Histopathology was available in 67 (34.9%) lesions and revealed benign findings exclusively. The remaining 125 (65.1%) lesions did not exhibit changes during the follow-up period and were, therefore, considered negative for malignancy.
  
  
  CONCLUSIONS
  The frequency of malignancy in breast lesions classified as BI-RADS 2 is zero. As a consequence, breast biopsies are unnecessary in these cases.
authors: Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna (AKH), Waehringer-Guertel 18-20, 1090 Vienna, Austria. Electronic address: claudio.spick@meduniwien.ac.at.
authors: C
authors: C
authors: Spick
authors: Diagnostikum Graz-Südwest, Weblinger Guertel 25, 8054 Graz, Austria. Electronic address: dieter.szolar@diagnostikum-graz.at.
authors: D H M
authors: DH
authors: Szolar
authors: Diagnostikum Graz-Südwest, Weblinger Guertel 25, 8054 Graz, Austria.
authors: M
authors: M
authors: Tillich
authors: Diagnostikum Graz-Südwest, Weblinger Guertel 25, 8054 Graz, Austria.
authors: P
authors: P
authors: Reittner
authors: Diagnostikum Graz-Südwest, Weblinger Guertel 25, 8054 Graz, Austria.
authors: K W
authors: KW
authors: Preidler
authors: Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna (AKH), Waehringer-Guertel 18-20, 1090 Vienna, Austria. Electronic address: pascal.baltzer@meduniwien.ac.at.
authors: P A
authors: PA
authors: Baltzer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult