Sonographic and pathologic findings in typical and atypical medullary carcinomas of the breast

Purpose. We investigated whether there was a relationship between the sonog raphic and histologic appearances of medullary carcinomas of the breast to determine whether sonography is helpful in the differentiation of typical a nd atypical medullary carcinomas. Methods. We retrospectively reviewed the histologic slides and sonograms of 20 patients who had been diagnosed with medullary carcinoma of the breast. We then classified the carcinomas as typical or atypical based on strict h istologic criteria. We also evaluated the relationship between sonographic findings and the histologic reclassification. Results. Eight (40%) of the 20 medullary carcinomas were classified as typi cal, and 12 (60%) were classified as atypical. On sonography, a smooth outl ine was visualized in 6 (75%) of the 8 typical medullary carcinomas but in none of the 12 atypical carcinomas. A jagged margin was sonographically vis ualized in 10 (83%) of the 12 atypical carcinomas, and a focal irregularity in the margin was visualized in 2 (17%) of the 12 atypical carcinomas. Fou r of the typical medullary carcinomas had posterior enhancement, and 9 of t he atypical medullary carcinomas showed retro-tumoral shadowing. The differ ence in tumor-margin regularity between typical and atypical medullary carc inomas was found to be statistically significant (p < 0.001) using the 2-ta iled Fisher's exact test. Conclusions. To prevent overdiagnosis of medullary carcinoma, a thorough pa thologic review of the entire tumor is recommended if sonography shows a ja gged margin or a margin with focal irregularity. (C) 2000 John Wiley & Sons , Inc.