Small Intestine and Colon Pathology 2 Flashcards
What are the two branches of inflammatory bowel disease?
crohns disease and ulcerative colitis
Which one - UC or CD - will affect only the colon an drectum?
ulcerative colitis
Which is continuous and which has skip lesions?
UC is continuous
CD has skip lesions
What will you see pathologically with ulcerative colitis
- dense lymphoplasmacytic inflammatory infiltrate
- crypt architecture alteration with branched crypts
- neutrophil crypt abscesses
these features will be seen in a uniform fashion thorughout the affected area
What will you see pathologically with crohns disease
- apthous ulcer formation with neutrophilic infiltrate (fissuring ulcers extending into submucosa)
- non-caseating granulomas
- grossly will see cobblestoning due to the fissuring
- fat wrapping around to anti-mesenteric side
involvement will be patchy - normal mucosa will be right next door
Which one has transmural involvement and which only invovles the mucosa?
UC is just mucosa
CD can be transmural
What are the risks associated with the transmural involvement in CD?
stricture formation or perforation with associated with serositis
Compare and contrast the CLINICAL presentations of UC and CD?
UD: bouts of bloody diarrhea with mucus discharge. lower abomdinal pain and cramps, tenesmus with proctitis
CD: variable presentation with mild diarrhea, fever, abdominal pain,
note that 10-20% of people with CD or UC will have extra-intestinal disease like sclerosing colangitis, erythema nodosum, pyoderma gangrenosum, iritis/uveitis
Define and describe diversion colitis
After a diverting ostomy, the blind distal segment of the colon is excluded form fecal stream
this means that the bacteria in that segment don’t get food and won’t make any short chain fatty acids for the colonocytes and you get a colitis
if the fecal stream is re-established, the colitis regresses
Define and describe radiation enterocolitis
epithelial damage occuring acutely due to radiation
chronic injury is often ischemic resulting from vascular injury with occlusion of blood vessels
patients can develop ulcers, strictures, fistulas and serosal adhesions - patchy erythema, hyalinization and thickening of blood vessel walls
radiation fibroblasts can be seen
Define and describe neonatal necrotixing enterocolitis
transmural necrosis of the bowel due to bacterial overgrowth in the first week of life in premature infants
get will be made in the wall of the intestine which can be seen as air bubbles within the wall
happens because they have impaired GI defenses to mucosal injury
What are the two types of microscopic colitis?
lymphocytic colitis
collagenous colitis
(treat with glucocorticoids)
What is the typical pathologic and clinical presentation for lymphocytic colitis?
you get increased lamina propria chronic inflammation (especially plasma cells) along with increased intra-epithelial lymphocytes and surface epithelial damage
crypt architecture is intact
presents with chronic watery diarrhea - no blood
What is the typical pathologic and clinical presentation for collagenous colitis?
A band of subepithelial collagen is seen in addition to the above inflammatory changes
crypt architecture is intact
also chronic watery diarrhea - no blood
State the classes of drugs commonly implicated in drug induced enterocolitis.
NSAIDs
chemotherapeutic agents
antibiotics leading to pseudomembranous colitis
Define and describe irritable bowel syndrome.
it’s chronic, relapsing abdominal pain, bloating and changesin bowel habits in the absense of any known causative agent that could explain the symptoms
it’s split into different subtypes based on stool consistency: constipation predominant, diarrhea preodminant, mixed-subtype and unsubtyped
pathogenesis unknown
Define and describe sigmoid diverticulitis
formation of multiple diverticulae, usually in the sigmoid colon
the diverticulae (tics) can become inflamed to form diverticulitis
pathogenesis related to increased intra-luminal pressure in the sigmoid colon from a lack of fiber in the diet
What are the common complications of sigmoid diverticulitis
Most people with diverticulae are asymptomatic unless you develop diverticulitis, in which case, perforation, fistula formation, obstruction, abscesses are potential complications
you can also get an inflammatory colitis referred to as diverticular disease-associated colitis
Define and describe solitary rectal ulcer syndrome
It’s a disorder caused by malfunction of the puborectalis muscle leading to excessive straining on defacation
straining results in prolapse which contributes to ulceration and formation of inflammatory polyps that can bleed
presents with bloody stools, pain with defecation and alternating constipation and diarrhea
Describe the clinical significance and morphology of inflammatory polyps
This is just a normal reaction to inflammation in the GI tract - not a neoplastic process
associated with conditions like solitary rectal ulcer syndrome, ulcerative colitis or crohn’s disease
can occur anywhere along the GI tract
sometimes called inflammatory pseudopolyps in UC and DC
Describe the clinical significance and morphology of juvenile (retention) polups
A hamartomatous polyp that occurs in young children and adults - can be sporadic or as a result of a polyposis syndrome
affect colon and rectum, typically solitary unless associated with a juvenile polyposis syndrome
sporadics have NO icnreased risk of malignancy, but people with juvenile polyposis syndrome are at higher risk for aenocarcinomas
polyp is smooth, unilobular with an erythematous cap of eroded tissue - histologically filled with multiple dilated mucin filled crypts leading to the term mucin retention polyp
can bleed if symptomatic
Describe the clinical significnance and morphology of Peutz-Jaghers polyps
polyp that occurs in peutz-jeghers syndrome
mucocutaneous hyperpigmentation and multiple polyps in the small bowel, colon and stomach
have a characteristic arborizing smooth muscle pattern - frequently peunculated
patients can present in childhood with GI bleeding and intussusception
Describe the clinical significance and morphology of a hyperplastic polyp
Usually occuring in the colon - most common type of adult colonic polyp
they are small and usually found in left colon (usually rectum) - can be single ot multiple
probably just a proliferative polyp without significant malignant potential. However, they need to be distinguished form sessile serrated adenomas and serrated adenomas, which are neoplastic polyps
Describe the clinical significance and morphology of adenomatous polyps
a neoplastic polyp characterized by dysplastic glandular proliferation
it can consist largetly of a tubular proliferation of glands or a more villous proliferation
usually in colon but can be in small bowel - esp ampulla of duodenum
can be precursors to adenocarcinoma, although most do not become maliganant. Needs to be completely removed either way
Describe the clinical significance and morphology of sessile serrated adenoma
it’s a sessil polyp that looks like a hyperplastic polyp, but it can be a precursor to adenocarcinoma
lack the classic adenomatous epithelium of the conventional adenoma
often seen in right colon
complete polypectomy on colonoscopy is necessary
Describe the clinical signifiance and morphoogy of a serrated adenoma
This exhibits serration along the uniform eiosinophlic dysplastic epithelium
also can be precursors for adenocarcinoma, so do polypectomy
How can you differentiate a sessile serated adenoma from a hyperplastic polyp?
the hyperplastic polyps will have crypts that narrow down into Vs at the bottom
the sessile adenoma crypts widen at the bottom
Think back….If someone has indeterminate colitis, what lab tests can help differentiate UC and CD?
CD is ASCA positive
UC is pANCA positive
WHat are the major complications of UC?
fulminant colitis with toxic megacolon and perforation
WHat are the major complications of CD?
small bowel stricutres, bowel obstruction, bowel perfortaoin from fistula formation
perianal fistulas, enterocutaneous fistulae, rectovaginal fistulas, enterovesicle fistulas.
WHat’s the neoplastic conern with IBD?
both can cause dysplasia leading to adenocarcinoma
What are some of the hypotheses regarding IBS pathogenesis?
- decreased/increased colonic contraction and transit times
- excess bile acid synthesis or malabsorption of bile acids
- disturbances in enteric nervous system function
- immune activation or shift in gut microbiome
What are the Rome III diagnostic criteria for IBS?
recurrent abdominal pain or disomfort at least 3 days per month in the last 3 months associated with 2 or more of the following:
- improvement with defacation
- onset associated with a change in frequency of stool
- onset associated with a change in form of stool
Why are people with Peutz-jegher syndrome at higher risk for adenocarcinoma?
they have a loss of function mutation of STK11 which is a tumor suppressor gene
