Calcifications of lobular carcinoma in situ of the breast: Radiologic-pathologic correlation

OBJECTIVE, Because lobular carcinoma in situ is thought to be an incidental finding at breast pathology, the finding of lobular carcinoma in situ at core biopsy poses a diagnostic dilemma of radiologic-pathologic concordance. The purpose of this article is to describe the radiologic-pathologic correlation of calcifications associated with lobular carcinoma in situ of the boast. MATERIALS AND METHODS. Between July 1999 and July 2000, seven excisional biopsies resulted in findings of lobular carcinoma in situ of mammographic calcifications, The radiographic features of the calcifications were characterized by the Breast Imaging Reporting and Data System lexicon, and pathologic features were reviewed. RESULTS. Two forms of lobular carcinoma in situ were associated with calcifications: the classic form with small, uniform cells, and the pleomorphic form with larger cells frequently associated with central necrosis, On mammography, all calcifications were clustered, punctate, high density, and smaller than or equal to 0.5 mm, although mammographically visible calcifications found in the pleomorphic type tended to be larger and more dense. Additionally, infiltrating lobular carcinoma was found after surgical excision in two (40%) of five patients with pleomorphic lobular carcinoma in situ. CONCLUSION. Calcifications can be associated with lobular carcinoma in situ and therefore concordant at stereotactic core biopsy. The classic form may be incidental and clinically innocuous, The pleomorphic form is morphologically similar to ductal carcinoma in situ and may have a greater tendency for invasion.