Peutz-Jeghers syndrome is also called intestinal polyposis-cutaneous pigmentation syndrome. It is an inherited or sporadic condition characterized by the development of hamartomatous polyps in the stomach, small or large intestine of the affected individual.
The risk of subsequent gastrointestinal cancers originating in the polyps is increased to about 15% by the age of 50 years. This risk rises to almost 60% by the time the patient is 70 years old.
The rate of occurrence has been estimated variously, and ranges from 1 in 25,000 to 1 in 300,000.
Cause of Peutz-Jeghers Syndrome
The inherited form is caused by a mutation in the STK11 (or LKB1) gene, which is a tumor suppressor gene. This is transmitted as an autosomal dominant condition. The mutation leads to an abnormal or deficient gene product which cannot regulate cell division properly. As a result, polypoid abnormalities of the mucosa occur, associated in many cases with cancerous changes. The odds are that any child born to an individual who has this mutation will have the genetic defect is 50%.
The sporadic form is not caused by any identifiable mutation in this gene. These two forms are found to occur with almost equal prevalence.
A person may show the following symptoms and signs of the condition:
- Clubbing of the extremities
- Dark-colored freckles in the area of the lips in the neonatal period, or dark spots on the mucosa of the mouth and of the skin around the eyes, nostrils or anus, mostly in childhood. These become less visible as the child grows. They are present in just over 8 of every 10 patients with this syndrome.
- Abdominal cramping pain.
- Recurrent intestinal obstruction.
- Gross or microscopic malena or bloodstaining of feces.
Diagnosis and Management
Diagnosis of this condition is based upon the presence of intestinal polyposis, pigmented spots on the skin and/or mucosa, and a positive family history. All features may not be present or symptomatic to the same extent in all individuals, so the syndrome is often underdiagnosed.
The presence of colonic polyps is detected by a colonoscopy. Small intestinal polyps require an X-ray examination after a barium meal, in which the opaque barium coats the internal surface of the small intestinal mucosa. Thus irregularities caused by the presence of the polyps will be revealed on the X-ray taken subsequently.
Another option is a fiberoptic flexible endoscopy involving the imaging of the small intestine by a swallowed endoscopic camera.
Associated features include intestinal intussusception and benign aural tumors.
Tests on the complete blood count may show the presence of anemia. Genetic testing is useful to detect the mutation. Occult blood in the stools is looked for by the stool guiac test.
If the polyps are symptomatic, immediate surgery is planned to remove the problem. Blood loss from bleeding polyps should be suspected and tested for. If present, the blood count should be built up with supplementary iron. Preventive polypectomy is often carried out if the number of polyps is manageable. In some cases, colectomy is more feasible.
Regular monitoring for the development of malignancy is a must.
The condition may lead to acute complications such as intussusception, or to long-term problems including cancerous tumors, intussusception, ovarian cysts, and sex-cord tumors in the ovary.
In addition to digestive tract tumors, cancers may form in the breast (50%), lungs (15%), pancreas (36%), ovaries (20%), and the cervix/uterus (19%). Genetic testing may show the presence of this mutation in about 95% of patients. It allows genetic counseling for other family members.