OVERDIAGNOSIS OF MEDULLARY CARCINOMA - A MAMMOGRAPHIC-PATHOLOGICAL CORRELATIVE STUDY

PURPOSE: To evaluate the mammographic features of medullary carcinoma, to determine the frequency of pathologic overdiagnosis of this neopla sm, and to assess whether mammography can distinguish true from atypic al medullary carcinomas, since this distinction has important prognost ic implications. MATERIALS AND METHODS: Retrospective review revealed 25 patients with an initial pathologic diagnosis of medullary carcinom a. Histopathologic slides and mammograms were reviewed. RESULTS: After review of histopathologic slides, 14 (56%) lesions were classified as medullary carcinomas and 11 (44%) as atypical medullary carcinomas. A t mammography, a circumscribed mass was present in four of the 14 (28% ) medullary carcinomas and in one of the 11 (9%) atypical medullary ca rcinomas (P = .34), an indistinct mass was present in seven of the 14 (50%) medullary carcinomas and in five of the 11 (45%) atypical medull ary carcinomas (P = .86), and an obscured mass was present in two of t he 14 (14%) medullary carcinomas and in three of the 11 (27%) atypical medullary carcinomas (P = .62). Calcification, which was present in o ne of the 11 (9%) atypical medullary carcinomas, and a spiculated bord er, which was present in one of the 11 (9%) atypical medullary carcino mas, were not observed in medullary carcinomas (P = .44). CONCLUSION: At mammography, medullary carcinoma was usually an uncalcified mass wi th indistinct or circumscribed borders. Atypical medullary carcinoma m ay be misdiagnosed as medullary carcinoma. Mammography could not relia bly help distinguish true medullary carcinomas from atypical medullary carcinomas.