Peutz-Jeghers polyposis

Definition: This autosomal dominant condition is characterized by the development of hamartomatous polyps throughout the gastrointestinal tract and muco-cutaneous pigmentation.

The distinction from other polyposes is not usually problematic but the clinical diagnosis may be less straightforward in formes frustes.

Although the polyps frequently occur in the colon, they are largest and most numerous in the small bowel, and the condition typically presents with small bowel obstruction or intussusception in the second or third decades.

The polyps are typically multilobated with a papillary surface and resemble tubulovillous adenomas grossly. The epithelium covers a core of arborizing smooth muscle.

There may be misplacement of mucin-secreting epithelium into the submucosa, muscularis propria and beyond the bowel wall, causing mimicry of well-differentiated or mucinous adenocarcinoma.

Dysplasia is uncommon, but there is an increased risk of colorectal cancer and extra-colonic malignancy in P-JS.

Extra-colonic tumors

The principal sites of extra-colonic tumors are pancreas, stomach, breast, ovary (sex cord tumors), testis (Sertoli cell tumors), and cervix (adenoma malignum) (See "Peutz-Jeghers disease").

Genetics

Mutations in the LKB1 (STK11) gene on chromosome 19p13 are found in approximately 50% of affected families. The phenotype is more severe in families with a truncating mutation than a missense mutation or when no mutation is found in LKB1.

Synopsis

 hamartomatous polyps
 digestive Peutz-Jeghers polyposis
 gastrointestinal hamartomatous polyps (stomach to rectum)
 multiple Peutz-Jeghers polyps

See also

 Peutz-Jeghers disease or Peutz-Jeghers syndrome