Oral tongue cancer in a patient with hereditary nonpolyposis colorectal cancer: A case report and review of the literature.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disorder characterized by mutations of mismatch repair genes leading to the early development of multiple malignancies. The most common malignancy is colorectal cancer but there is a strong association with malignancies of the ovary, endometrium, small intestine, stomach, skin, brain, and pancreas. We report a case of a 35-year-old female with a history of known HNPCC who presented with adenocarcinoma of the small intestine as well as a synchronous oral tongue squamous cell carcinoma. The patient underwent a combined oncologic surgery involving a hemiglossectomy, selective neck dissection, and partial small bowel resection. Despite the wide range of malignancies seen in patients with HNPCC, no cases of oral cavity cancer have previously been reported. This represents the first case in the literature of oral cavity cancer in a patient with HNPCC.