Coexistence of gastrointestinal stromal tumour and colorectal adenocarcinoma: Two case reports.

TThis paper reports two rare cases of patients with synchronous gastrointestinal stromal tumour (GIST) and colorectal adenocarcinoma (CRC) where adjuvant FOLFOX chemotherapy was administered concurrently with imatinib mesylate. The first case is a 67-year-old woman with a large gastrointestinal stromal tumour with metastasis masking a co-existing primary colon cancer, which was diagnosed after tumour response to imatinib mesylate. The second case presents a 61-year-old male with a primary colon cancer and a suspected metastatic lymph node, later confirmed to be a co-existing primary gastric GIST during colon surgery. While colorectal cancer is the third most common cause of cancer-related death in North America, the prevalence of GISTs remains rare. To date, very few cases of synchronous GIST and CRC adenocarcinoma have been reported in the literature. Although the coexistence of these two tumour types is rare, it is important to be aware of their disease patterns.