Peutz-Jeghers syndrome
Meaning of Peutz-Jeghers syndrome: An inherited condition pairing dark freckle-like spots on the lips with polyps throughout the gut and a raised lifetime cancer risk.
Definition of Peutz-Jeghers syndrome
Peutz-Jeghers syndrome is an inherited condition marked by dark blue-brown spots on the lips, inside the mouth and on the fingers, together with numerous polyps growing through the small intestine and colon. Those polyps are a particular type known as hamartomas. Most cases trace to a fault in a single gene, and the condition carries a raised risk of several cancers.
What are the two visible features?
The spots appear in infancy or early childhood as flat dark marks on the lips, around the mouth, and on the fingers and toes. Many fade during adult life, but those on the inside of the cheek usually persist. The polyps are the more consequential feature. They grow on a stalk, mostly in the small intestine, and cause bleeding, slow blood loss and pain. A large polyp can drag one section of bowel inside the next, a blockage called intussusception, which is a common way the condition first announces itself in a child.
How is it inherited?
A fault in the STK11 gene, also written LKB1, is found in most families. The gene normally restrains cell growth, so losing one working copy removes part of that brake. The pattern is dominant, meaning a single altered copy is enough and each child of an affected parent has an even chance of inheriting it. Some people are the first in their family to carry the change, so an absent family history does not exclude it. Genetic testing confirms the diagnosis and identifies relatives who carry the same change.
Which cancers are linked?
| Site | Note |
|---|---|
| Small intestine | Raised risk of small intestine cancer, an otherwise uncommon tumor |
| Colon and rectum | Risk of colorectal cancer is substantially above average |
| Stomach and pancreas | Both occur more often than expected |
| Breast | Risk approaches that seen in some other inherited breast cancer syndromes |
| Ovary, cervix and testis | Distinctive uncommon tumor types are associated |
Because the risk spans several organs and begins young, surveillance with endoscopy and imaging is started in childhood and continued through life.
Also known as
Used in a sentence
Peutz-Jeghers syndrome was suspected when pigmented spots on the lips accompanied recurrent small bowel obstruction.
Good to know
The dark spots often fade after childhood while the polyps and the raised cancer risk remain, so their absence in an adult does not rule the syndrome out.