Adenocarcinoma of the colon associated with hyperplastic polyposis.

A 24-year-old woman presented with a history of chronic watery diarrhea associated to abdominal pain and weight loss. Her father had died of cirrhosis at the age of 47 and her grandmother had died from colorectal cancer at the age of 69. A colonoscopy revealed multiple sessile polyps scattered throughout the colon (ranging from 3 to 15mm), and a large, villous looking lesion located in the ascending colon (Fig. 1). The lesion was biopsied and several polypectomies were performed. The histology was compatible with an adenoma with high grade dysplasia and hyperplastic polyps, respectively. Total colectomy with ileo-rectal anastomosis was performed. The specimen analysis revealed a mucinous adenocarcinoma of the ascending colon and the existence of 70 hyperplastic polyps and serrated adenomas in the remaining mucosa, none of which presented high grade dysplasia or carcinoma. Molecular analysis of the adenocarcinoma revealed a microsatellite stable tumor, BRAF mutation and CpG Island Methylator Phenotype (CIMP high). No KRAS mutation was identified. Genetic analysis was negative for germline mutations in APC and MYH genes.