Abstract
Metaplastic breast cancer (MBC) is a rare and heterogeneous malignancy characterized by the presence of both epithelial and mesenchymal elements. Among its variants, MBC with osteoclastic giant cells is extremely uncommon and presents diagnostic challenges because of its diverse histopathological and imaging features. We report the imaging features of a patient with pathologically proven MBC with osteoclastic giant cells as follows: a high-density mass with microcalcification was revealed on mammography; and a microlobulated, mixed cystic and solid mass with posterior acoustic enhancement was revealed on ultrasound. MRI revealed a round mass with circumscribed margins, rim enhancement and high T1-weighted signal intensity due to internal haemorrhage, heterogeneous T2-weighted high-signal intensity and initial fast enhancement and rapid washout kinetics that was classified as BI-RADS 5. Left mastectomy was performed, and the final diagnosis was consistent with that of MBC.