Colorectal cancer in a patient younger than 20 years of age: report of a case and a review of the Japanese literature.

This article presents a case of advanced cancer of the transverse colon seen in an 18-year-old woman who underwent a potentially curative resection. The histological type of cancer was well-differentiated adenocarcinoma. After reviewing the clinicopathological features of 110 colorectal cancer cases in patients younger than 20 years of age compiled from the Japanese literature, the high incidence of poorly differentiated carcinoma (51.5% for poorly differentiated adeno-carcinoma, signet-ring cell carcinoma, mucinous carcinoma, and undifferentiated carcinoma) and of more advanced stages (67.1% for clinical stages IIIb and IV) were found to be characteristic for patients with colorectal cancer younger than 20 years of age. The presence of more advanced disease and the high incidence of poorly differentiated carcinoma thus seem to be related to the low postoperative survival rates. The 2-year survival rate was 19.8% and the 5-year survival rate was 8.8% in colorectal cancer patients younger than 20 years of age.