Multifocal matrix-producing mammary carcinoma mimicking lobular carcinoma on core biopsy – A case with long survival reported

We report the clinico-pathologic features of a patient with extensive multifocal matrix-producing mammary carcinoma which mimicked invasive pleomorphic lobular carcinoma on biopsy. Neoplastic cells both in areas with and without matrix were positive for EMA and vimentin. Cytokeratin antibodies were negative, and there was no immunoreactivity for ER, PR, HER2, CD10, GCDF15, p63, or E-cadherin. The proliferative activity was low (<5%) in areas both with and without matrix production. Despite significant tumor volume and high-grade histologic features, an 8-year follow-up has been uneventful.