title: Non-mass lesions on screening breast ultrasound.
abstract: OBJECTIVE
  The purpose of this study was to determine the significance of a non-mass lesion (NML) which is recognized during screening breast ultrasound (US).
  
  
  METHODS
  We included patients with a NML on screening breast US and no suspicious finding on mammography between March 2008 and June 2012. The final diagnoses were based on pathology results and a clinical or sonographic follow-up for more than 12 months. We calculated the incidence, likelihood of malignancy, and positive predictive value (PPV) of biopsy with a review of imaging and histopathological findings.
  
  
  RESULTS
  A total of 17868 screening breast US were performed in 8856 asymptomatic patients. Ninety-five NMLs were detected in 88 patients (1.0%). Among the 93 lesions that were followed or confirmed histopathologically, 2 (2.2%) were malignant, 89 (95.6%) were benign, and 2 (2.2%) were high risk lesions. The likelihood of malignancy in a NML on screening breast US was 2.2% and the PPV of biopsy was 6.3% (2 of 32).
  
  
  CONCLUSIONS
  The likelihood of malignancy for a NML on screening breast US was greater than 2%. It could be classified as a BI-RADS category 4a lesion and tissue diagnosis is warranted. This provides the potential management guidelines for a NML in screening patients and further prospective studies in a large, multicenter screening population are required.
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Republic of Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Republic of Korea. jhrad@dau.ac.kr.
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Radiology, Haeundae Sharing and Happiness Hospital, Busan, Republic of Korea.
authors.forename: Seonmi
authors.initials: S
authors.lastname: Baik
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun
authors.initials: E
authors.lastname: Cho
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Republic of Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Dong-A University Medical Center, Dong-A University College of Medicine, Busan, Republic of Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kwon
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015994:Incidence; D008137:Longitudinal Studies; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary / Q000706:statistics & numerical data*