Primary mucinous cystadenocarcinoma of breast with sternal metastasis: A diagnostic challange

The WHO categorizes the breast tumors in various distinct histological types based on cell morphology and architecture. A widely accepted fact that aggressive nature of cancer can be determined by its type, grade, nodal status, metastasis holds ground even era immunohistochemistry (IHC) molecular. An extremely rare variant primary carcinoma belongs to family mucin producing sharing same histology as mucinous cystadenocarcinoma ovary pancreas. tumour typically occurs postmenopausal women with a median patient age 61 years. Due rarity these tumors, there is an extreme paucity literature this topic. We report case 35 year old female left lump presternal swelling. Breast lumpectomy total sternectomy was done final diagnosis given Primary sternal Estrogen receptor (ER) Progesterone receptors (PR) positivity.