title: Extra-mammary findings in breast MRI.
abstract: OBJECTIVE
  Incidental extra-mammary findings in breast Magnetic Resonance Imaging (MRI) may be benign in nature, but may also represent a metastasis or another important lesion. We aimed to analyse the prevalence and clinical relevance of these unexpected findings.
  
  
  METHODS
  A retrospective review of 1535 breast MRIs was conducted. Only axial sequences were reassessed. Confirmation examinations were obtained in all cases.
  
  
  RESULTS
  285 patients had a confirmed incidental finding, which were located in the liver (51.9%), lung (11.2%), bone (7%), mediastinal lymph nodes (4.2%) or consisted of pleural/pericardial effusion (15.4%). 20.4% of incidental findings were confirmed to be malignant. Positive predictive value for MRI to detect a metastatic lesion was high if located within the bone (89%), lymph nodes (83%) and lung (59%), while it was low if located within the liver (9%) or if it consisted of pleural/pericardial effusion (6%). The axial enhanced sequence showed superior sensitivity to unenhanced images in detecting metastatic lesions, especially if only smaller (≤10 mm.) lesions were considered.
  
  
  CONCLUSIONS
  The prevalence of metastatic incidental extra-mammary findings is not negligible. Particular attention should be to incidental findings located within the lung, bone and mediastinal lymph nodes.
authors.affiliation: Department of Bio-Imaging and Radiological Sciences, Catholic University - Policlinic A. Gemelli, L.go A. Gemelli 8, 00168 Rome, Italy. pierluigi.rinaldi@rm.unicatt.it
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Rinaldi
authors.forename: M
authors.initials: M
authors.lastname: Costantini
authors.forename: P
authors.initials: P
authors.lastname: Belli
authors.forename: M
authors.initials: M
authors.lastname: Giuliani
authors.forename: E
authors.initials: E
authors.lastname: Bufi
authors.forename: R
authors.initials: R
authors.lastname: Fubelli
authors.forename: D
authors.initials: D
authors.lastname: Distefano
authors.forename: M
authors.initials: M
authors.lastname: Romani
authors.forename: L
authors.initials: L
authors.lastname: Bonomo
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008207:Lymphatic Metastasis / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D012189:Retrospective Studies