Polyposis syndromes, hereditary

Genetically determined polyposis syndromes with disseminated polyps of the colon and possibly the entire gastrointestinal tract. These syndromes exhibit extracolonial symptoms at different frequencies (e.g. Peutz-Jeghers syndrome: lentiginosis of the skin and the mucous membranes close to the skin or in Gardner syndrome (epidermoid cysts, osteomas, desmoids). They require special diagnostic and possibly therapeutic attention.

Depending on the syndrome, there is an obligatory precancerous condition. In this respect, different diagnostic and therapeutic strategies must be followed.

Relevant polyposis syndromes are:

• Familial adenomatous polyposis: FAP (obligate precancerous lesion) (D12.6)
• Gardner syndrome: Familial adenomatous polyposis with epidermoid cysts (35%) and osteomas (85%). The skin changes and bone abnormalities often manifest themselves before the intestinal polyps develop.
• Turcot syndrome: Familial adenomatous polyposis with glio-/medulloblastomas of the brain.
• Attenuated familial adenomatous polyposis (late-manifesting rare variant of FAP)
• MUTYH-associated polyposis (MAP; rare polyposis syndrome with autosomal recessive inherited germline mutations in the MUTYH gene)
• Birt-Hogg syndrome (BHD syndrome/Integumen: Multiple, skin-colored, flesh-colored or waxy shiny, relatively coarse, 2-5 mm large, hemispherical asymptomatic papules, often also oral; caused by a germline mutation in the folliculin(FLCN) gene )
• Hamartous polyposis syndromes (rare, increased risk of colorectal cancer)
  • Familial adenomatous polyposis (mutation in the SMAD4/BMPR1A genes)
  • Familial juvenile polyposis (mutations in the SMAD4/BMPR1A genes)
  • Juvenile polyposis of childhood (mutations in the BMPR1A+PTEN genes)
  • Peutz-Jeghers syndrome (Q85.8; mutations in the STK11/LKB1 genes)
  • Cowden syndrome (mutation in the genes SMAD4/BMPR1A/ integument: facial tricholemmomas, oral papillomatosis, acral keratoses)
  • Hyperplastic polyposis syndrome (HPS)

Mostly asymptomatic incidental finding as part of a colon diagnosis. The polyps become clinically conspicuous due to bleeding, obstruction or carcinomatous degeneration.

Digital rectal examination, recto/colonoscopy. In the case of larger rectal adenomas, rectal endosonography to clarify endoscopic removability

Possibly MRI sellink of the small bowel and video capsule endoscopy to detect small bowel polyps in polyposis syndromes.

Important: the entire colon should always be searched for further adenomas: complete colonoscopy required (detection of > 1 adenoma in 1/3 of cases).

In case of a suspected clinical diagnosis, a genetic clarification and, if necessary, family consultation must be carried out. FAP patients are to be monitored endoscopically from the age of 10. Examination for extracolonic manifestations (see below for the individual entities). In the case of hamartose polyposis, preventive examinations from the 10th year of life.

The aim must always be to completely remove the adenoma in healthy tissue. The method used depends on the size and risk of carcinoma:

- Adenomas: ≤ 5 mm: ablation with biopsy forceps + histology

> 5 mm: Loop ablation in toto with base + histology

Larger adenomas that cannot be safely removed completely by snare can be removed by various surgical procedures:

• Transanal endoscopic microsurgery (TEM)
• Endoscopic submucosal dissection (ESD)
• laparoscopic or conventional resection procedures.

A polyp is any macroscopically recognizable tissue proliferation of the mucosa that rises above the level of the mucosa and thus protrudes into the lumen. Depending on the nosology and prognosis, a distinction is made between:

• Non-neoplastic polyps
• Neoplastic polyps. These are referred to as epithelial tumors, also known as adenomas.