Clinicopathological and immunohistochemical study of mucinous carcinoma of breast

Introduction: Mucinous carcinoma (also known as colloid carcinoma) is a particular type of breast cancer characterized by the presence of extracellular mucin and is linked with a more favorable prognosis than invasive breast carcinoma of no special type. Mucinous carcinoma of the breast is an uncommon form of breast tumor, often presenting as a lobulated, moderately well circumscribed mass on mammography, sonography, and MRI imaging. It accounts for 1 to 7% of all breast cancers. Pure mucinous breast carcinomas are rare and account for about 2% of all primary breast carcinomas. Metastatic disease happens at a lower rate than in other types of invasive carcinoma. Aims and Objectives: To study the Clinic pathological and Immuno histochemical features of Mucinous Carcinoma Breast. Materials and Methods: We present our 2 year study from January 2016 to December 2018 on mucinous carcinoma of breast. Patients diagnosed with Pure MC and Mixed MC according to WHO classifications of tumors of breast 2012 were studied. Specimens were routinely processed and stained with Hematoxylin and eosin. Results: We identified 25 patients with mixed and pure mucinous breast cancer, the tumor size varied greatly from 2 to 19 cm in diameter. A subset of mixed mucinous carcinomas (8 cases) showed neuroendocrine differentiation or other associated premalignant lesions. Conclusion: Mucinous carcinoma of the breast is a rare entity with a favourable prognosis. In our study pure mucinous carcinoma accounted largest group and are seen at a younger age when compared to mixed mucinous carcinoma. Almost all the cases presented in stage p T2. Majority of the Pure MC did not show evidence of secondary deposit, whereas 50% cases of Mixed MC show secondary deposit. Most of cases of pure mucinous and mixed mucinous showed hormone receptor positivity. Older age at presentation, lesser tumor size and stage, hormonal receptor positivity are observed in our study, all of which are associated with good prognosis.