Hereditary non-polyposis colorectal cancer

Dr Craig Hacking and A.Prof Frank Gaillard et al.

Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition which predisposes to a host of malignancies, including colorectal carcinoma. It is considered the most frequent form of hereditary colorectal cancer. Diagnosis requires evaluation using clinical criteria (see: Amsterdam criteria for HNPCC).

Typically HNPCC patients present in their forties and fifties with colorectal cancer 2, or with one of the associated malignancies. It is 5 times more common than familial adenomatous polyposis syndromes (FAP) 6.

HNPCC is due to mutations in DNA mismatch repair (MMR) genes 2, resulting most frequently in colorectal carcinoma (80% lifetime risk) as well as extracolonic malignancies, including 1-2:

Radiographic features are related to the underlying conditions:

The high risk of colorectal carcinoma warrants screening of the colon from 25-40 years of age 2 and may require colectomy. With close surveillance and resection of any adenomas which develop, the risk of CRC can be reduced by 60% 3.

Due to a high number of extracolonic tumours, various screening programs should also be instituted, such as transvaginal ultrasound screening of the uterus and ovaries and serum CA-125 2.

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Article information

rID: 1614
Section: Syndromes
Synonyms or Alternate Spellings:
  • Hereditary non polyposis colorectal cancer (HNPCC)
  • Hereditary non polyposis colorectal cancer
  • Lynch syndrome
  • Hereditary non-polyposis colorectal carcinoma
  • Lynch II syndrome

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