摘要：

A 28-year-old female presented to the endocrine surgery clinic with complaints of the right breast lump for 3 months. Clinical examination revealed a 3 cm × 2 cm hard lump in the upper outer quadrant, suspicious of carcinoma breast with clinical staging of T2N0M0. Three years before this, she was diagnosed to have adenocarcinoma of the rectum and had undergone treatment. On serial follow-up, there was no evidence of locoregional recurrence of the disease. Ultrasound imaging of the right breast was suggestive of BI-RADS V lesion, highly suspicious of primary breast malignancy. However, the core biopsy was reported to be mucinous adenocarcinoma with immunohistochemical markers suggestive of a colorectal primary. Metastasis to the breast from a primary colorectal carcinoma is an exceedingly rare clinical entity. The imaging findings may not yield any characteristic differences between primary breast cancer and breast cancer due to metastasis from other cancerous primary. Biopsy of the lesion with relevant immunohistochemical markers remains the mainstay of the diagnosis. The overall prognosis is poor, and the treatment comprises oral capecitabine as a palliative agent with or without wide local excision of the metastatic breast lesion.

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