Pure and mixed XXXX of the breast: pathologic basis for differences in mammographic appearance.

@entity1 @entity82 @entity0 @entity5 @entity189 @entity1653
OBJECTIVE: It is important to differentiate pure and mixed @entity189 of the breast because the former have a more favorable prognosis. We correlate histopathologic findings with mammographic findings for 20 @entity1 with pure or mixed @entity189 to determine differential characteristics and their pathologic basis. MATERIALS AND METHODS: We searched our pathology database of 2219 consecutive @entity1 with a diagnosis of @entity0 and found that 31 (1.4%) had @entity189 . Eleven @entity1 were excluded because the mammograms (n = 6) or the microscopic slides (n = 5) were not available. The remaining 20 @entity1 , who were 37-92 years old (mean, 64 years), were the subjects of the study. Their clinical records, mammograms, and microscopic slides were reviewed. @entity5 size was based on the maximum mammographic diameter or measured diameter of the excised @entity5 . RESULTS: Seventeen @entity1 (85%) had @entity5 that were mammographically apparent. Histopathologic review confirmed 15 pure @entity5 and five mixed @entity5 having an overall mean diameter of 3.4 cm. The pure- @entity5 group contained three incidentally detected @entity5 (all < or = 0.8 cm in diameter); six that had a circumscribed, lobular contour on mammograms (mean diameter, 3.6 cm); and six that had a poorly defined, irregular contour (mean diameter, 1.2 cm). One of the mammographically apparent small pure @entity5 contained histologically confirmed @entity1653 . All pure @entity5 had microscopically evident circumscribed margins that could have accounted for the circumscribed mammographic appearance of the larger masses. All mixed @entity5 had mammographically and histologically evident irregular margins because of the associated @entity82 and infiltrative margins of the nonmucinous component (mean diameter, 5.3 cm). CONCLUSION: There are differences in the mammographic appearances of pure and mixed @entity189 that have a histopathologic basis. Circumscribed, lobular margins on mammograms are characteristic of large pure @entity5 and are the result of their microscopically evident circumscribed margins and expansile growth pattern. Irregular margins on mammograms are more characteristic of mixed @entity5 , regardless of @entity5 size, and are attributable to the fibrotic and infiltrative nature of the nonmucinous component.
