Peutz-Jeghers syndrome
What is it?
Peutz-Jeghers syndrome is a rare genetic, inherited, autosomal dominant syndrome characterized by hamartomatous-type intestinal polyps that can involve the entire digestive tract and characteristic hyperpigmented spots called "melanotic spots." Intestinal polyps are of the hamartomatous type (different from those in familial adenomatous polyposis). "Melanotic spots" are 1-5 mm blackish-brown freckle-like patches that appear in childhood and involve mainly lips, oral mucosa, and various areas of the skin. It can cause various cancers, such as those of the pancreas, stomach, small intestine and colon. It is caused by a germline mutation (pathogenic variant) in the STK11/LKB1 gene, which is responsible for the disease in 80-94% of cases. The STK11/LKB1 gene encodes for a molecule (called protein) that acts as an oncosuppressor (prevents the formation of tumors). If this gene is mutated, as happens in Peutz-Jeghers syndrome, it will lose this function.
Which are the symptoms?
The cumulative risk of developing malignant neoplasms of the stomach is about 29% at the age of 15–64 years, colorectal adenocarcinoma - about 39% at the age of 15–64 years, and, finally, of the small intestine - about 13%. There is also an increased risk of developing neoplasms of the pancreas (11-36%), mammary glands (32-54%), ovaries (18-21%), testicles (9%), lungs (7-17%).
How is it diagnosed?
The main criteria on the basis of which Peutz-Jeghers syndrome is clinically suspected are as follows. During an examination, the physician will perform a thorough examination to check the following parameters:
- Two or more histologically confirmed Peutz-Jeghers polyps.
- Family history of Peutz-Jeghers syndrome and at least one histologically confirmed Peutz-Jeghers polyp
- Characteristic mucocutaneous pigmentation and family history of Peutz-Jeghers syndrome
- Characteristic mucocutaneous pigmentation and at least one Peutz-Jeghers polyp
In such cases, genetic testing for germline pathogenic variants using two DNA sequencing techniques called Next Generation Sequencing (NGS) and Multiplex ligation-dependent probe amplification (MLPA) is indicated.
How is it treated?
In individuals with Peutz-Jeghers syndrome, preventive strategies are aimed at identifying preneoplastic lesions early. Prompt treatment of these will prevent the development of advanced neoplasia. Prevention consists therefore in the regular surveillance of body districts at risk of developing neoplasia, in particular
- Straight intestine: The first colonoscopy is offered at an early age and then repeated every 1-3 years, if negative. Polyps will be removed by elective polypectomy surgery.
- Stomach: The first esophago-gastro-duodenoscopy (EGDS) is offered young age and then repeated every 1-3 years, if negative. Polyps will be removed by elective polypectomy.
- Small Intestine: Enteroresonance or enteroscopy with videocapsule is offered starting at age 8 years and repeated every 1-3 years. Polyps will be removed by elective polypectomy surgery.
- Pancreas: Since the risk of developing pancreatic cancer is 30-60% at age 70, pancreatic surveillance is recommended as part of research protocols regardless of whether or not family members have ever had pancreatic cancer
- Breast and ovary: breast MRI, gynecologic ultrasound.
Where do we treat it?
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