title: Breast magnetic resonance imaging characteristics in women with occult primary breast carcinoma.
abstract: BACKGROUND
  Occult breast cancer without clinically or mammographically detectable breast tumor is an uncommon presentation.
  
  
  OBJECTIVE
  To assess the role of breast MRI in women with metastatic carcinoma and an occult primary, and to define the MRI characteristics of the primary breast tumor.
  
  
  METHODS
  This retrospective study evaluated 20 women with metastatic carcinoma of unknown origin who underwent breast MRI between 2000 and 2006. Four women were excluded, leaving 16 in the study group. Probability of malignancy was assessed according to BIRADS classification. MRI performance in detecting lesions and evaluating disease extent was assessed, with the gold standard being surgical or biopsy pathology.
  
  
  RESULTS
  MRI detected suspicious lesions in 15 patients. Lesion size ranged from 0.4 to 7 cm (median 1.5 cm). MRI detected a single lesion in 6 patients (40%), multifocal disease in 3 (20%), multicentric disease in 4 (27%), and bilateral breast lesions in 2 (13%). In 13 patients MRI depicted the primary breast cancer. Initial treatment was surgical in 9; MRI correctly estimated disease extent in 6 (67%), underestimated disease extent in 1 (11%), and overestimated it in 2 (22%). Four patients had biopsy followed by chemotherapy; one had multicentric disease and one had multifocal disease. MR findings were false positive in two patients and false negative in one.
  
  
  CONCLUSIONS
  MRI is sensitive in detecting the primary tumor and beneficial in assessing tumor extent. Small size and multiple foci are common features. We suggest that bilateral breast MRI be part of the evaluation of women with metastatic carcinoma and an occult primary.
authors.affiliation: Department of Diagnostic Radiology, Hadassah-Hebrew University Medical Center (Ein Kerem Campus), Jerusalem, Israel. sivanlieberman@hotmail.com
authors.forename: Sivan
authors.initials: S
authors.lastname: Lieberman
authors.forename: Tamar
authors.initials: T
authors.lastname: Sella
authors.forename: Bella
authors.initials: B
authors.lastname: Maly
authors.forename: Jacob
authors.initials: J
authors.lastname: Sosna
authors.forename: Beatrice
authors.initials: B
authors.lastname: Uziely
authors.forename: Miri
authors.initials: M
authors.lastname: Sklair-Levy
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000601:surgery; D012189:Retrospective Studies