Lynch syndrome, often called hereditary nonpolyposis colorectal cancer (HNPCC), is an inherited disorder that increases the risk of many types of cancer, particularly cancers of the colon (large intestine) and rectum, which are collectively referred to as colorectal cancer. People with Lynch syndrome also have an increased risk of cancers of the stomach, small intestine, liver, gallbladder ducts, urinary tract, brain, and skin. Additionally, women with this disorder have a high risk of cancer of the ovaries and lining of the uterus (endometrial cancer). Women with Lynch syndrome have a higher overall risk of developing cancer than men with the condition because of these cancers of the female reproductive system. In individuals with Lynch syndrome who develop cancer, the cancer typically occurs in their forties or fifties.
People with Lynch syndrome may occasionally have noncancerous (benign) growths in the colon, called colon polyps. In individuals with this disorder, colon polyps occur at a younger age but not in greater numbers than they do in the general population. [from
MedlinePlus Genetics]