What is characteristic of Peutz-Jeghers Syndrome is the association of gastrointestinal polyps and mucocutaneous pigmentation. The risk of gastrointestinal and extraintestinal malignancies is significantly increased.
Polyps may occur throughout the entire gastrointestinal tract but are most common in the small intestine (with the highest density in the jejunum, followed by the ileum and the duodenum). Polyps can occur outside of the gastrointestinal tract as well (renal pelvis, urinary bladder, ureters, lungs, nose, and gall bladder). Their malignant potential is currently unclear. The polyps can cause complications such as intestinal obstructions, rectal prolapse, or severe gastrointestinal hemorrhaging.
The average age when the first gastrointestinal symptoms appear is 10 years of age, with the first polypectomy on average being performed at the age of 13.
It is rare for the characteristic melanocytic maculae to exist at birth already; they typically develop by age 5. The pigmentation fades during puberty and adulthood. The maculae are dark blue to dark brown in color and occur most commonly in the perioral region, on the eyes and nostrils, on the buccal mucosa, and in the perianal region. Hyperpigmented maculae on the fingers are also common. No risk of malignancy is associated with melanocytic maculae.
Female PJS patients have an increased risk of sex cord tumors with annular tubules (SCTAT) and mucinous tumors of the ovaries and tubes, which regularly develop bilaterally and have a benign progression.
Male PJS patients have an increased risk of large calcifying Sertoli cell tumors (LCST) of the testicles. These tumors release estrogen and generally do not exhibit any malignant transformation.