Metaplastic Breast Cancer with Chondroid Differentiation

Background: Metaplastic breast cancer (MBC) cancer is a rare subtype of breast carcinoma and carries a worse prognosis. Chondroid differentiation is the rarest among all its histologic subtypes. We report a case of MBC with chondroid differentiation and review its clinicopathological details, genetic basis, and management. Case presentation: A 56-year female presented with right-sided large breast lump. She noticed this lump 4 months before presenting. Trucut biopsy was suggestive of invasive ductal carcinoma. She underwent breast conservation surgery and histology was consistent with MBC with chondroid differentiation, pT2N3aM0. Tumour was triple-negative for ER, PR, and Her-2- neu receptors. Adjuvant treatment with chemotherapy followed by radiotherapy was given and she has been doing fine during 11 months of follow-up. Conclusion: The MBC is an uncommon subtype with heterogeneity in biological and morphological features and its knowledge is paramount while evaluating a breast lump. Understanding the pathologic and molecular basis is imperative in developing the targeted therapy to improve outcomes.