Synchronous gist, colon and breast adenocarcinoma with double colonic polyp metastases

Long term survivors of breast cancer are at risk of developing distant metastasis years after the initial treatment. We report a case of breast adenocarcinoma with colonic polyp metastases, as well as synchronous primary colonic adenocarcinoma and a gastric GIST.

An 83 year old female underwent colonoscopy for rectal bleeding. This showed a primary colonic adenocarcinoma, a pedunculated polyp in the ascending colon and two polyps in the sigmoid colon. A staging CT scan did not show distant metastasis, but revealed a small gastric GIST which was managed conservatively. A right hemicolectomy showed a T3N0 colonic adenocarcinoma and a polyp contained metastatic adenocarcinoma from a breast primary. The patient had undergone surgery 30 years ago for an invasive lobular carcinoma. Further clinical assessment demonstrated an impalpable grade II Invasive ductal carcinoma in the contralateral breast. She was started on hormonal treatment and at 18 months follow-up, she was well with stable disease.

Invasive lobular cancer is the most common histological type of breast cancer that metastasizes to the colon. There is no consensus on the management of breast cancer metastasis to the gastrointestinal tract. Co-existence of a GIST and an adenocarcinoma at two separate locations is uncommon. These are two different cancer entities and it is unclear whether these two are related by as causal relationship.

This is a rare case of three distinct tumours; association between them is unlikely. However, the case highlights the importance of a multidisciplinary approach to cancer treatment.