Curriculum · Gastroenterology
Peutz-Jeghers syndrome
What it is
Peutz-Jeghers syndrome is an autosomal dominant condition caused by mutation of the STK11 gene, which encodes serine threonine kinase LKB1. Its classic triad is mucocutaneous pigmentation, hamartomatous polyps mainly in the small intestine, and complications.
How it presents
About 95% of patients have hyperpigmented macules that typically affect the lips (perioral lentigines), buccal mucosa, genitals, palms and soles. The same finding is called melanotic spots on the lips in one source and pigmented freckles on the lips, face, palms and soles in another. Dark spots over the lips and oral mucosa in a young patient who comes in with vomiting, abdominal distension and constipation is the pattern to know.
How it is diagnosed
Multiple hamartomatous polyps are found throughout the gastrointestinal tract, mainly the small bowel. Intestinal obstruction, for example intussusception, may lead to the diagnosis, and a target sign on CT fits intussusception due to Peutz-Jeghers polyps.