Metaplastic Carcinoma of Breast: A Rare Pathological Entity- A Study of 10 Cases from Tertiary Care Centre in Northern India

Abstract

Introduction: Metaplastic Carcinoma of Breast (MCB) is a rare heterogeneous neoplasm characterised by a mixture of adenocarcinoma with dominant areas of spindle cells, squamous and other mesenchymal differentiation. The reported incidence is 0.2% of all breast cancers. Aim: To study the clinicopathological profile of MCB. Materials and Methods: This retrospective cross-sectional descriptive study included 10 cases of MCB who underwent mastectomy and biopsies at BPS GMC Khanpur Kalan, Sonipat, Haryana, India from March 2013 to February 2020. Results: Out of 10 cases, five cases were MCB Not Otherwise Specified (NOS) type, four cases were MCB with mesenchymal differentiation and one case showed rhabdomyosarcomatous differentiation. The right breast was involved in nine cases. The mean size of tumour was 8 cm with range of 3 to 16 cm. Five patients were treated by modified radical mastectomy and axillary dissection, four patients had lumpectomy and one patient underwent mastectomy. Half of the patients were below 40 years with the mean age being 36.8 years and range of 21-60 years. On Immunohistochemistry (IHC), 90% (9/10) cases were triple negative. Conclusion: MCB, although rare has to be diagnosed and excised at the earliest as the prognosis is predicted to be worse similar to other triple negative breast carcinomas. Ductal Carcinoma in Situ (DCIS) at the tumour periphery and co-expression of vimentin and cytokeratin would help to clinch the diagnosis in difficult situations.