Peutz-Jeghers syndrome overview

# Overview
Peutz-Jeghers, also known as Hereditary Intestinal Polyposis Syndrome, is an autosomal dominant genetic disorder caused by a mutation in the STK11 (LKB1) tumor suppressor gene. It is  characterized by the appearance of multiple benign hamartomatous polyps in the gastrointestinal tract, which increase the risk of cancer in the gastrointestinal tract. PeutzJeghers syndrome ia also associated with hyperpigmented macules on the lips and oral mucosa (melanosis). The incidence of Peutz-Jeghers syndrome is approximately 0.03 to 4 per 100,000 individuals worldwide. If left untreated, patients with Peutz-Jeghers syndrome may progress to develop rectal bleeding, anemia, intussusception, bowel obstruction. Abdominal CT and MRI may help in the diagnosis of Peutz-Jeghers disease. Screening for intestinal and extraintestinal cancers is recommended for patients with Peutz-Jeghers disease. Surgery is the mainstay of treatment.

# Historical Perspective
In 1998, STK11 (LKB1) mutations were first identified in the pathogenesis of Peutz-Jeghers syndrome. The syndrome is named after Jans Peutz (1886-1957), a Dutch physician, and Harold Jeghers (1904-1990), an American physician who had successively described the association between polyposis and the mucocutaneous macules.

# Pathophysiology
Peutz-Jeghers syndrome is transmitted in an autosomal dominant pattern. Polyps of Peutz-Jeghers syndrome are usually non-neoplastic hamartomas. It is thought that Peutz-Jeghers syndrome is the result of deletion or partial deletion of STK11 (LBK1) gene, located on chromosome 19p13.3. Mucutaneous pigmentation (macules) are caused by pigment-laden macrophages in the dermis.

# Causes
Peutz-Jeghers syndrome is caused by a mutation in the STK11 (LKB1) tumor suppressor gene.

# Differentiating Peutz-Jeghers Syndrome from other Diseases
Peutz-Jeghers syndrome must be differentiated from other diseases that cause hamartomatous polyps and mucocutaneous pigmentation, such as Cowden syndrome, BannayanRileyRuvalcaba syndrome, and juvenile polyposis.

# Epidemiology and Demographics
The prevalence of Peutz-Jeghers syndrome is estimated to be in the range of 0.8 to 2.8 in 100000 and it affects individuals between the ages of 10 to 30 years.

# Risk Factors
Common risk factor in the development of Peutz-Jeghers syndrome is the presence of family history of Peutz-Jeghers syndrome.

# Screening
Screening for cancerous lesions by small intestine radiography, esophagogastroduodenoscopy (EGD), colonoscopy, pancreatic ultrasound, pelvic ultrasound, mammography, and Papanicolaou test (Pap test) is recommended among patients with Peutz-Jeghers syndrome.

# Natural History, Complications and Prognosis
If left untreated, patients with Peutz-Jeghers syndrome may progress to develop rectal bleeding, anemia, intussusception, bowel obstruction, and abdominal pain. Common complications of Peutz-Jeghers syndrome include colon cancer and cachexia. Prognosis is generally good with treatment.

# Diagnosis

## Diagnostic Criteria
The diagnosis of Peutz-Jeghers syndrome is made when at least 2 of the following 3 diagnostic criteria are met: positive family history, mucocutaneous pigmentation, and presence of hamartomatous polyps.

## History and Symptoms
The hallmark of Peutz-Jeghers syndrome is hamatomatous polyps. A positive history of mucucutaneous hyperpigmentation and rectal bleeding is suggestive of Peutz-Jeghers syndrome. The most common symptoms of Peutz-Jeghers syndrome include abdominal pain, fatigue, and weight loss.

## Physical Examination
Common physical examination findings of Peutz-Jeghers syndrome include mucocutaneous hyperpigmentation, abdominal tenderness due to intussusception, bowel obstruction, and pallor due to anemia.

## Laboratory Findings
Some patients with Peutz-Jeghers syndrome may have positive stool guaiac test and anemia, which are usually suggestive of colon cancer.

## Chest X Ray
On chest x-ray, Peutz-Jeghers syndrome is characterized by a mass with widening of the mediastinum, atelectasis, consolidation, and pleural effusion.

## Abdominal CT
Abdominal CT scan may be helpful in the diagnosis of Peutz-Jeghers syndrome. Findings on CT scan suggestive of Peutz-Jeghers syndrome include multiple polyps, intussusception, and bowel obstruction.

## Abdominal MRI
Abdominal MRI scan may be helpful in the diagnosis of Peutz-Jeghers syndrome. Findings on MRI suggestive of Peutz-Jeghers syndrome include multiple polyps along the distribution of the gastrointestinal tract.

## Abdominal Ultrasound
Abdominal ultrasound may be helpful in the diagnosis of Peutz-Jeghers syndrome. Findings on abdominal ultrasound suggestive of Peutz-Jeghers syndrome include multiple polyps and small bowel distention. Abdominal ultrasound is also used to exclude pregnancy in young females with Peutz-Jeghers syndrome presenting with abdominal pain.

## Other Imaging Studies
Barium x-ray maybe helpful in the diagnosis of Peutz-Jeghers syndrome. Findings on barium x-ray suggestive of Peutz-Jeghers syndrome include multiple polyps.

## Other Diagnostic Studies
Other diagnostic studies for Peutz-Jeghers syndrome include colonoscopy, which demonstrates multiple polyps in the colon, and capsule endoscopy, which demonstrates multiple polyps in the small intestine.

# Treatment

## Medical Therapy
There is no medical treatment for Peutz-Jeghers syndrome. Depending on the associated cancer, radiotherapy or chemotherapy may be considered.

## Surgery
Surgery is the mainstay of treatment for Peutz-Jeghers syndrome. Surgical options include polypectomy, laparotomy in case of intussusception, and laser cosmetic therapy may be considered for mucocutaneous pigmentation.

## Primary Prevention
There are no primary preventive measures available for Peutz-Jeghers syndrome. However, if there is a positive family history, intrauterine genetic testing may help in early diagnosis.

## Secondary Prevention
Secondary prevention strategies to detect intestinal and extraintestinal malignancies in Peutz-Jeghers syndrome include enteroscopy and colonoscopy.