GI polyps

Question 1

Polyp types: Hamartomas versus Adenomas

Answer 1

Hamartomas: disorganized growth of normal tissue (tissue indigenous to the site).
Adenomas: all have dysplasia, precancerous, crowded, enlarged disorganized nuclei, mucin depletion, increased mitosis. Tubular versus villous

Question 2

Hamartomas

Answer 2

Hamartomas: disorganized growth of normal tissue (tissue indigenous to the site). dilated cysts filled with mucin, abundant lamina propria and prominent inflammatory infiltrate, haphazard arrangement.
- ulcerative surface prone to auto-infarction, highly vascular.
Types of hamartomas:
- Juvenile polyps
-Peutz-Jeghers hamartoma
-Ganglioneuromas.

Question 3

Hamartoma types

Answer 3

-Juvenile polyps: pedunculated, round to multilobulated, 1-3 cm.
- Peutz-Jeghers: sessile or pedunculated with lobulated surface, has arborizing strands of smooth muscle extending to polyp surface
- Ganglioneuromas: composed of ganglion and Schwan cells with fibrous tissue. These are fully differentiated neuronal tumors that do not contain immature elements, associated with NF1 and PHTS

Question 4

Juvenile polyp

Answer 4

-Hamartoma, pedunculated, round to multilobulated, 1-3cm

Question 5

Peutz-Jeghers polyp

Answer 5

-Hamartoma, sessile or pedunculated with lobulated surface.
-arborizing strands of smooth muscle extending to polyp surface

Question 6

Ganglioneuromas

Answer 6

-composed of ganglion and Schwann cells with fibrous tissue
-Fully differentiated neuronal tumors that do not contain immature elements.
-Associated with NF1 and PHTS

Question 7

Adenomas

Answer 7

Adenomas: all have dysplasia, precancerous, crowded, enlarged disorganized nuclei, mucin depletion, increased mitosis.
Tubular versus villous

Question 8

FAP syndrome

Answer 8

• Most common in kids
  -Gene: APC, Autosomal dominant, 30% de novo
• Adenomas in colon (also SI and stomach). Adenoma to carcinoma sequence.
• Hepatoblastoma under 5 years.
  -Extraintestinal: bone abnormalities, supernumerary teeth, congenital hypertrophy of retinal pigment epithelium. Desmoid development s/p surgery. Thyroid and adrenal cancer. CNS glioblastoa (Turcot’s)
• Surveillance: colonoscopy at age 11 years (or at first symptoms). US/AFP in kids <5 years.
• Management: colectomy based on polyp burden, advancing dysplasia.

Question 9

MutYH Associated Polyposis

Answer 9

• Gene: MutYH (gene repair), Autosomal recessive, leads to muted APC gene.
• Adenomas in Colon, stomach and SI, Adenoma to Carcinoma, other tumors.
  -Extraintestinal manifestations are rare.
  Surveillance: similar to FAP.
  -Management based on polyp location and amenability to polypectomy

Question 10

Lynch Syndrome

Answer 10

• MCC of hereditary colorectal cancer.
• Gene: MMR Gene(s). Also ECAM1. Autosomal dominant, variable expression, de novo is rare.
• Polyp: Adenoma. Accelerated Adenoma to Carcinoma sequence, Endometrial cancer, Synchronous and Metachronous cancers.
• Extraintestinal: CNS (turcot syndrome), Skin (Murre Torre Syndrome). Cancer risk in multiple other organs.
• Surveillance: colonoscopy Q1-2 years once adenomas found.
• Management: colectomy, prophylactic salpingophrenectomy/hysterectomy.

Question 11

Juvenile Polyposis Syndrome (5 or more juvenile polyps)

Answer 11

Gene: SMAD4, BMPR1A. ~50% AD, variable expression,
-multiple phenotypes:
- Infantile: PLE. anemia. early colectomy
- Juvenile polyposis coli:
- Generalized JPS: pan-GI.
- JPS/hereditary hemorrhagic telangiectasia (HHT): SMAD4.
Polyp: Hamartomas in colon (BMPR1A), or throughout GI tract (SMAD4).
Extraintestinal manifestations: clubbing, polydactyly, macrocephaly, heart disease, double renal pelvis and ureter, bifid uterus and vagina, undescended testes, supernumerary teeth, mental retardation, thyroid cancer, gastric cancer, pancreatic cancer.
Surveillance: colonoscopy Q2 years, cerebral and pulm AVM screening.
Management: colectomy when polyp burden is unmanageable.

Question 12

Peurz-Jeghers Syndrome: PJS

Answer 12

Gene: STK11 (LKB1). Autosomal dominant. lots of de novo mutations.
- PJS hamartomas: SI > stomach > colon. Increased lifetime cancer risk: GI tract, pancreas, lungs, testes, breast, uterus, ovary.
Extra-intestinal: peri-oral mucocutanous pigmentation, bleeding, anemia, intussusception, recurrent surgery with intestinal resection. sertoli cell tumors of ovary and testicles.
Surveillance: labs for anemia, SI surveillance by video capsule or MRE. Testicle US.
Management: intraoperative enteroscopy with all laparotomies for removal of SI polyps.

Question 13

PTEN Hamartoma syndrome

Answer 13

Unique findings: multiple polyps of multiple histologies.