Polyposis Syndromes Flashcards
Colorectal polyps can be classified as
adenomatous
hamartomatous
hyperplastic
neoplastic
inflammatory.
Colorectal Polyposis Syndromes Summary
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Colorectal Polyposis Syndromes 2
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Colorectal Polyposis Syndromes 3
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Familial adenomatous polyposis (FAP)
- Autosomal dominant
- mutation in the adenomatous polyposis coli (APC) tumor suppressor gene
- located on chromosome 5q21.
- Most mutations are found between codons 168 and 1640
- Two of the most significant being 1061 and 1309.
FAP is defined as
- greater than 100 synchronous adenomas
or
fewer than 100 with a positive family history. - Polyps, predominately found in the rectum and left colon, develop in adolescence
If untreated, the risk of colorectal malignancy is nearly
100% by 35 to 40 years of age.
screening colonoscopy should be performed at
10 to 12 years of age and continue annually.
With the predilection for polyp development in the left colon and rectum, a yearly flexible proctosigmoidoscopy can be completed instead of a formal colonoscopy. If adenomatous polyps are appreciated on sigmoidoscopy, a formal colonoscopy should ensue.
A screening esophagogastroduodenoscopy (EGD) is typically performed around
20 years of age
Gastric Lesions in FAP
- Hyperplastic gastric fundic glad polyps
> low malignant potential > 30% to 90% of patients - Gastric adenomas > potential malignant progression > 10%– 30% > occur in the antrum.
Where is Duodenal adenomas Mostly Found
- Most commonly found around the ampulla of Vater
What is the percentage of Patients with FAP will have Dudenal adenoma ? When will it appear ? and how much will have Cancer
- Found in more than 95% of patients with FAP
- Develop approximately 15 years later than colonic polyps
- Duodenal cancer, typically diagnosed around 50 years of age, occurs in 5% to 10% of Patients
The risk of developing cancer after 10 years of follow-up for each stage
Stage I is 0
Stage II and III 2%
Stage IV 36%
Spigelman stage
see
Low Risk Adenomas
Small tubular adenomas
low-grade dysplasia,
> can be biopsied and observed.
High-risk adenomas, and Tx ?
villous
> 1 cm
severe duodenal polyposis
high-grade dysplasia
or stage IV disease
> offered a pancreas-preserving duodenectomy
Those with cancer, Tx
- Pancreaticoduodenectomy.
- Chemoprevention with nonsteroidal antiinflammatory agents (sulindac, celecoxib) can result in polyp regression
Suggested Interval to Next Duodenoscopy (Years)
see
Common extraintestinal manifestations of FAP
- osteomas
- congenital hypertrophy of the retinal pigmented epithelium (CHRPE)
- epidermoid cyst
- dermoids.
- Benign osteomas of the mandible, skull, and tibia are the most common extraintestinal finding occurring in upward of 80% of patients.
- CHRPE is not specific to FA
> four or more areas of large patchy fundic discoloration is pathognomonic - Epidermoid cysts occur approximately 50%
Other extraintestinal manifestations, though rare, include
supernumerary teeth
cerebellar medulloblastoma
cancers of the liver, biliary tree, adrenal glands, and thyroid.
The second leading cause of death associated with FAP.
Duodenal cancer
What Percentage of FAP will Develop Desmoid
Desmoids develop in 15% to 30% of patients
What is the Third Most Common of death in FAP
Desmoid
Risk factors associated with the development of desmoids are
- mutations in the 3 ΄ end of the APC gene
- female gender
- extraintestinal manifestations
- family history of desmoid disease.
Extraabdominal desmoids are best treated with
- Surgical extirpation with a 1-cm margin
> recurrence is high with documented rates of 20% to 50%.
> Early excision is recommended to decrease the size of the resultant abdominal wall defect.
Intraabdominal/ retroperitoneal desmoids Tx
- The primary treatment is medical and includes
> nonsteroidal antiinflammatory agents (sulindac, celecoxib)
estrogen antagonists (tamoxifen, toremifene, raloxifene)
chemotherapy (vinblastine, methotrexate, doxorubicin, Adriamycin, dacarbazine)
Radiotherapy can be used for palliative measures
Resection with completely uninvolved margins (R0) will result in recurrence, what percentage
50%
Attenuated FAP (aFAP) Difference from FAP
- presents at a later age (30s– 40s)
- fewer than 100 polyps
- predominantly found in the right colon
- If untreated, the risk of colorectal malignancy is nearly 100% by 59 years of age.
- gastric adenomas, desmoids, and CHRPE are typically not seen in aFAP.