Unusual metastatic patterns of invasive lobular carcinoma of the breast.

Invasive lobular carcinoma of the breast has similar patterns of metastatic disease when compared to invasive ductal carcinoma; however, lobular carcinoma metastasizes to unusual sites more frequently. We present a 65-year-old female with a history of invasive lobular breast carcinoma (T3N3M0) treated with modified radical mastectomy and aromatase-inhibitor therapy who underwent a surveillance PET scan, which showed possible sigmoid cancer. Colonoscopy with biopsy revealed a 3 cm sigmoid adenocarcinoma.