14. Diverticulosis of the colon. Pathology of the colonic polyps.

Congenital malformations of the colon?

Aganglionosis

What is aganglionosis?

Malformation where there is a lack of neurons and ganglion cells of the myenteric and submucos plexus

- the affected part is very stenotic and above this region the colon is dilated

Ischaemic colitis?

Ischaemia of the colon - leads to a gangrenous infarction it its severe enough

Why gangrenous infarction?

Because of the presence of bacteria

Ischaemia of the colon can be?

- Occlusive

- Non-occlusive

Vascular diseases of the colon?

Angiodysplasia

What is angiodysplasia?

Small vascular malformation in the gut

- manifests as rectal bleedings which occurs episodically

What is diverticular disease?

= Diverticulosis

Outpouchings of mucosa and submucosa (pseudodiverticuli) that herniate through the colonic muscle layers

Why are the colonic diverticuli not real diverticuli?

Because for it to be a real diverticulum, the outpouching need to contain all layers of the intestinal wall

Where are the diverticula most common?

In the sigmoid colon

How does the colonic diverticula develop?

Develop under conditions of high intraluminal pressure

- associated with not eating enough fiber -> constipation -> increased pressure

Diverticulitis?

Inflammation of the diverticula

Complication of diverticulitis?

- Perforation -> peritonitis -> sepsis

- Ileus

- Fistulas

- Bleeding

Polyps of the colon and rectum?

- Hyperplastic polyps

- Sessile serrated polyps

- Hamartomatous polyps

- Adenomatous polyps

- Familial adenomatous polyposis

Hyperplastic polyps?

Hyperplasia of the epithelial cells, as well as delayed shedding

- benign and not precancerous

Hyperplastic polyps is often found where?

In rectum and sigmoid colon

Sessile serrated adenoma/polyp?

Polyps which have a serrated appearance

- have malignant potential-> precancerous

What are hamartomatous polyps?

Polyps of disorganized cells and tissue that is characteristic for the place where the polyp is found

- often associated with polyposis syndromes;

-> Peutz-Jeghers syndrome

-> Juvenile hamartomas

What are juvenile hamartomas?

Hereditary condition that is characterized by the presence of hamartomatous polyps in the digestive tract

What are Peutz-Jeghers syndrome?

Rare autosomal dominant disorder that is characterized by hamartomatous polyps in the whole GI-tract

- and mucocutaneous hyperpigmentation

Adenomatous polyps?

Polyps characterized by epithelial dysplasia

- precancerous lesion

What is familial adenomatous polyposis?

Autosomal dominant disorder, which is caused by the mutation of the APC gene

- manifests as 100-1000 polyps in the colon and rectum

Familial adenomatous polyposis vs. adenomatous polyps?

Morphologically indistinguishable

- only way to diagnose is to count that more than 100 polyps are present

What happens if a patient with FAP dont get treatment?

100% risk of developing colorectal adenocarcinoma