Imaging overview of metaplastic carcinomas of the breast: a large study of 71 cases

Objective: To review the clinical presentation, baseline imaging features, surgical management and final surgical pathology of metaplastic carcinoma of the breast. Methods: A total of 71 cases were identified over a 10-year period from two major UK breast cancer institutions. Imaging at diagnosis including mammography, ultrasound, MRI and CT scans and histological diagnosis were reviewed. Follow-up data including local and systemic recurrence were retrieved. Results: Of the 71 cases, 60 (84.5%) cases presented with a palpable lump. 60 (84.5%) cases showed a mass on mammography, of whom 47 (78.3%) cases were ill defined and 17.0% cases showed calcifications associated with a mass lesion. All 71 cases were seen as a mass on ultrasound. The imaging score was R3 or R4 in 26 cases and R5 in 47 cases. 16 patients underwent MRI with most (93.8%) showing a solid mass with central necrosis. No metastatic disease was seen in the 13 patients who underwent staging CT. Despite having a larger size, 50% of the cases successfully underwent breast conservative surgery. Positive axillary lymph nodes were seen in 11 (15.5%) cases. Conclusion: In this series, metaplastic cancers were palpable in 85% cases, tended to be large at the time of presentation and imaging showed characteristics of malignancy. Only 11 (15.5%) cases had nodal involvement. Advances in knowledge: Metaplastic carcinomas are often palpable and of large size at the time of presentation. Metaplastic carcinomas raise the concern for malignancy on mammography and ultrasound, warranting further biopsy. Metaplastic carcinomas tend to be grade 3 and triple receptor negative.