Introduction : Bilateral breast cancer is extremely rare presentation. Most of the cases of bilateral breast cancer are of lobular carcinoma type. Herewith we report a case of bilateral Invasive Breast Carcinoma (Not Otherwise specified). A case of a 47 year old female who presented with bilateral breast mass, right breast mass measuring 3.4 x 2 x 2 cm and left breast mass measuring 2.8x2.0x1.6 cm. Fine needle aspiration cytology of right breast mass was reported as positive for carcinoma cells. Patient was operated for left modified radical mastectomy 8.5 years back which was reported as Invasive Breast Carcinoma (IBC) - II and now, the patient was operated for right modified radical mastectomy which was reported as right sided Invasive Breast Carcinoma with medullary differentiation. The Richardson Bloom score was (3+3+3) =9 , Grade III. Conclusion: Metachronous bilateral breast cancer is an extremely rare presentation of breast cancer. Early detection of contralateral breast tumor is of utmost importance for appropriate management of these cases.

Keywords: Bilateral Breast Cancer; Invasive Breast Carcinoma; Breast Lump; Medullary Differentiation.