GI path Flashcards
Histo of normal esophagus
- stratified nonkeratinizing squamous epithelium
- proximal 1/3=striated muscle
distal 2/3=smooth muscle - GE junction (where rugal folds begin)
- Z-line (squamocolumnar junction): mucosal junction of squamous and columnar epithelium, may not correspond to GE junction when columnar metaplasia has occured
esophageal atresia and tracheoesophageal fistula
Def: Embryologic failure of tubal esophagus to connect mouth to stomach, ending in a blind pouch; fistula may connect segment to trachea
Clinical:
- 50% have associated congenital anomalies–VATER syndrome (Vertebral defects, Anal atresia, TrachEoesophageal fistula, and Renal dysplasia)
- Respiratory symptoms (aspiration pneumonia)
abnormal hedgehog signaling
normal gastroesophageal junction
stratified sqaumous of esophagus
simple columnar of gastric cardia
esophageal ring
Concentric, thin diaphragm of tissue in the distal esophagus, most commonly at GE junction (Schatzki’s ring
esophageal webs
- Eccentric, thin membranes of tissue in the esophagus, most commonly proximal region
- Plummer-Vinson syndrome: webs + iron deficiency anemia + glossitis; women; responds to iron supplementation
Esophageal diverticula
Outpouchings of the esophageal wall
- True = all layers, including muscle
- False = mucosa & submucosa only
- Zenker’s diverticulum = false, cervical esophagus, elderly (motor dysfx)
- Epiphrenic diverticulum = true, any age, just above diaphragm
Reflect underlying motor dysfunction
image=Zenker’s diverticulum
achalasia
def?
clinical?
microscopic?
Definition
Inability of the LES (lower esophageal sphincter) to relax after swallowing, resulting in periodic esophageal obstruction
Clinical
Dysphagia, odynophagia, regurgitation
inc. risk for squamous cell carcinoma
Microscopic Reduction or absence of myenteric ganglion cells
Symptoms: heartburn, acid regurg, dysphagia, globus sensation, chronic sore throat
Dx?
risk factors?
contributing factors?
Dx: GERD (Reflux of gastric acid into the esophagus with mucosal damage)
Risk Factors: Age, EtOH, tobacco (LES relaxation), chocolate
Contributing factors: hiatal hernia, weak LES, impaired esophageal peristalsis, delayed gastric emptying, inc gastric acid production
GERD
Hyperemia, vertical linear streaks represent superficial mucosal erosions/ulcers
GERD on bottom
squamous proliferation, papillae elongation, basal cell hyperplasia, inc. inflammation in lamina propria, decreased surface maturation
Note: biopsy findings are not specific! cannot make diagnosis w/ biopsy alone must have clinical info as well
Barrett’s esophagus
Def
Definition
Endoscopically recognizable columnar metaplasia of the esophageal mucosa that is confirmed pathologically to have intestinal metaplasia, the latter defined by goblet cells
Both the endoscopic and pathologic components should be present to establish BE.
Barrett’s esophagus: columnar metaplasia (intestinal metaplasia)+goblet cells
dysplasia in barrett’s
sequence of adenocarcinoma is metaplasia–>dysplasia–>carcinoma
Sx: dysphagia, food impaction
Hx: allergies, failed antireflux therapy
Tests: normal pH monitoring
Dx?
primary eosinophilic esophagitis (>15 eos/hpf from pts who lack a positive response to proton-pump inhibitors, have normal pH monitoring, or both)
herpes esophagitis
lateral margin of ulcer
cowdry A intranuclear inclusions (Multinucleation, chromatin Margination, nuclear Molding)
CMV esophagitis
- Base of ulcer
- Lg intranuclear inclusion with granular cytoplasmic inclusions
Candida esophagitis
- Immunosuppressed, Diabetics, recent Abx
- Pseudohyphae
esophageal varices: Dilatation of submucosal esophageal veins
most often due to portal hypertension secondary to cirrhosis
- *Mallory-Weiss laceration**
- at GE junction (usually on gastric side)
- Forceful vomiting/retching forces prox stomach through diaphragm
- Laceration may bleed profusely
- Acute esophageal rupture –> Boerhaave’s syndrome
Fundus, body
Parietal (oxyntic) glands
Pink = parietal cell
Blue/purple = chief cell
Cardia and Antrum
Cardiac/antral glands
Mucus cells
Congenital hypertrophic pyloric stenosis
- Concentric enlargement of the pyloric sphincter and narrowing of the pyloric canal that obstructs the gastric outlet
- palpable epigastric mass (“olive”)
-M:F 4:1
Mostly Caucasian; rare in blacks & Asians
-Possible genetic as well as environmental (drugs, infection in utero) pathogenesis
gastritis:
acute vs chronic vs reactive
Acute gastritis
Erosive/hemorrhagic
Chronic gastritis
Autoimmune
H. pylori associated
Lymphocytic (see text)
Granulomatous (see text)
Eosinophilic (see text)
Collagenous (see text)
Reactive gastropathy
Chemical (see text)
Sx: abrupt onset abdominal pain and bleeding
Hx: alchohol use, NSAIDS
Dx?
Most common etiology?
Path findings?
Therapy?
Dx: Acute erosive/hemorrhagic gastritis (stress gastritis) (Abrupt onset of ab pain & bleeding a/w ETOH, NSAIDs, or low hemodynamic state following trauma)
Due to Breakdown of mucosal barrier (Direct irritant action, Drug mechanism of action, Hypoperfusion)
Most common etiologies: NSAIDS, post-op state
Gross: Petechiae, erosions, ulcers
Microscopic: Limited to mucosa: superficial lamina propria hemorrhage, mucosal sloughing/necrosis, neutrophils
Therapy: Acid-supression (histamine blockers, proton-pump inhibitors)
30yo female presents with fatigue and dyspepsia.
Labs: megaloblastic anemia, B12 deficiency, increased gastrin
Hx: SLE
Biopsy of body of stomach
Dx?
Path?
Dx: autoimmune gastritis (Immune-mediated form of chronic gastritis, results in loss of parietal cells, hypo- or achlorhydria, vit B12 deficiency)
Clinical: Autosomal dominant, <5% of chronic gastritis, Women, Pernicious anemia (megaloblastic anemia d/t ↓vit B12), Other autoimmune diseases
Labs: inc. gastrin, decreased vit B12
Path: Lymphoplasmacytic inflammation in deep, glandular lamina propria; limited to body/fundus
Fundic gland damage by patchy lymphocytic infiltrates
Loss of glands over time–> atrophy (atrophic gastritis)
autoimmune gastritis
*intestinal metaplasia is precursor to dysplasia and gastric carcinoma
*ECL cell hyperplasia is precursor to neuroendocrine tumors
Helicobacter pylori gastritis
def?
clinical?
Definition: Chronic antral-predominant gastritis caused by H. pylori
Clinical: A/w peptic ulcer disease (stomach & duodenum), gastric lymphoma & carcinoma
H. pylori gastritis
Lymphoplasmacytic inflammation admixed with neutrophils in superficial mucosa
Pititis, cryptitis, crypt abscesses (neutrophils = “activity”) due to H. pylori gastritis
H. pylori gastritis
Line epithelium in mucus layer
(do NOT invade, but secrete toxins)
Menetrier’s disease
Definition: Body & fundus-restricted hyperplasia of foveolar (mucous cell) epithelium with hypoproteinemia
Clinical: dec plasma proteins (albumin) from gastric mucosa, dec acid production
Pathogenesis: TFG-alpha overexpression
Gross: Markedly thickened rugal folds in fundus & body (resembling brain)
Microscopic: Foveolar (mucous cell) hyperplasia –>corkscrewing
histo features of normal small bowel mucosa
-villous height-to-crypt depth ratio of 3:1 to 5:1
-
-lamina propria contains mild physiologic mix of plasma cells, lymphocytes, and occasional eosinophils
Brunner’s glands are in the duodenum. They are in the submucosa
produce mucin rich alkaline (bicarbonate) secretion that protects duodenum from stomach acid and lubricates
normal terminal ileum w/ peyer’s patches
endoscopic findings celiac disease
scalloping and loss of folds
histologic features of celiac disease
- increased intraepithelial lymphocytes with loss of so-called decrescendo pattern
- blunted villi and crypt elongation
- inc. plasma cells and lymphocytes in lamina propria (back is more “blue” and expanded from chronic inflammation)
Marsh classification
Used for classifying Celiac disease.
Most symptomatic celiac pts are Marsh3a-c.
classifies degree of villous blunting and crypt elongation
serologic tests for Celiac Disease
1) Anti-tTG IgA: highly sensitive and specific. Best test!
2) Serium IgA levels simultaneously tested to exclude IgA deficiency which would give false negative
True gold standard diagnosis of CD is clinical/pathological response to gluten-free diet.
Other less good tests:
- anti-endomysial IgA
- Anti-gliadin (used to monitor response to gluten free diet)
Genetics of Celiac Disease
almost all people w/ CD have MCH class II HLA-DQ2 or HLA-DQ8
absence makes diagnosis unlikely
but 20% of normal population have this, so not used for screening
Other conditions besides Celiac that might have increased IEL and/or villous blunting
- immune (common variable immunodeficiency, HIV entropathy, autoimmune disease)
- Infection (H. pylori, cryptosporidium, bacterial overgrowth, )
- NSAID injury
*NOTE: CVID mimics but has fewer plasma cells!
Diseases assoc. with celiac disease
- dermatitis herpetiform* (responds to GF diet)
- lymphocytic collagenous colitis
- lymphocytic gastritis
- refractory sprue
- collagenous sprue
- enteropathy-assoc. T cell lymphoma*
- small intestinal adenocarcinoma
- “test tubes in a rack” bases of crypts abut the muscularis mucosa
- mild degree of chronic inflammation in lamina propria is normal (lymphocytes, plasma cells, eosinophils, mast cells)
characteristic triangular folds of the colon
microscopic colitis
lymphocytic and collagenous colitis
pts have chronic watery (non-bloody) diarrhea and normal endoscopy
middle aged-elderly
assoc. with certain drugs (long-term NSAIDS) and celiac disease
lymphocytic vs collagenous colitis
Lymphocytic colitis:
- *F:M ratio of 3:1
- *increased IEL
- no inc. subepithelial collagen
- inc. lymphocytes, plasma cells and eosinophils in LP
- no architectural changes
Collagenous colitis:
- *F:M of 8:1
- *increased IEL
- *thickened subepithelial collagen
- inc. lymphocytes, plasma cells and eosinophils in LP
- no architectural changes
Inflammatory bowel diseases (3)
1) Ulcerative colitis
2) Crohn’s disease
3) Intermittent colitis
Gross pathology of IBD
active disease: erythematous, friable, edematous, ahaustral w/ or w/o ulcerations, pseudopolyps, cobblestoning
*biopsy alone can’t distinguish b/t Crohn or UC
Pathologic findings in UC
-distribution: continuous colonic involvement of mucosa beginning in rectum
Gross findings:
- inflammatory polyps
- lead pipe colon (loss of haustral folds)
- toxic megacolon
Microscopic changes: limited to mucosa
Pathologic findings in Crohn’s disease
- distribution: rectum usually spared, skip lesions, patchy disease both grossly and microscopically, disease can affect any part of columnar GI tract (classically terminal ileum)
- Gross findings:
- Long linear (bear claw-like) ulcers
- cobblestone mucosa
- creeping fat (mesenteric fat wrapping around serosal surface)
- strictures (muscularis hypertrophy and hyperplasia)
Microscopic changes:
- inflammatory change involving entire wall of bowel (Vs UC only in mucosa)
- “transmural inflammation”: chronic inflammation and lymphoid aggregates
- knife-like fissures
- granulomata
- combing fat
Mucosal changes in IBD
chronicity
activity
chronicity:
- architectural distortion
- metaplasia
- paneth cell metaplasia of left colon
- pyloric metaplasia (terminal ileum in Crohn disease)
-muscularis hypertrophy and hyperplasia
Activity: how much acute inflammation
- cryptitis: neutrophils in epithelium
- crypt abscess: collection of neutrophils in lumen of a crypt
chronicity in Crohn disease
- architectural distortion (villous blunting)
- pyloric metaplasia
- muscularis hypertrophy and hyperplasia (both muscularis mucosa and muscularis propria)
Acute self-limited colitis
- typically transient (2-4wks) colitis w/ diarrhea (sometimes bloody)
- most commonly assoc. w/ bacterial enterocolitis, can be viral or parasitic
- usually not biopsied but when done: biopsy has acute inflammation but no features of chronicity (distinguish from IBD, no architectural distortion, no paneth cell metaplasia, no MM hypertrophy)
C. difficile colitis
- related to previous antibiotic exposure
- “pseudomembranous colitis”:
- not diagnostic: DDx includes C. diff and ischemia
- PCR for C. diff toxins
- pseudomembranes composed of fibrin, mucin and neutrophils. glands typically lose epithelial cells (C. diff toxin affects cell adhesion)
Strictures in bowel
DDx?
- chronic ischemia (d/t fibrosis)
- crohn disease (d/t muscularis mucosae and propria hypertrophy and hyperplasia)
- tumor
- recurrent bouts diverticulitis
celiac disease
tip of villi w/ inc. IEL. architecture preserved so Marsh 1 lesion
IEL are dark blue dots, enterocytes are lighter and more elongated
celiac disease
small intestine is severely blunted so it looks completely flat
common variable immune deficiency mimics celiac diseae (but no plasma cells)
cryptosporidium mimics celiac disease
lymphocytic colitis. lamina propria filled with chronic inflammatory cells. No crypt distortion. No thickened subepithelial collagen band
lymphocytic colitis with surface damage (mucin depletion and reactive changes)
collagenous colitis. pink collagen bands under surface. No architectural distortion.
collagenous colitis. capilarries are entrapped in thickened subepithelial collagen band. lots of chronic inflammation in lamina propria and mildly inc. IEL and eosinophils.
IBD w/ features of chronicity.
cyrpts have lifted off muscularis mucosa and are bifurcated–>architectural distortion
Muscularis mucosae is thickened (MM hypertophy and hyerplasia)
terminal ileum w/ pyloric metaplasia
Pyloric metaplasia is feature of chronicity. glands look like pyloric glands of gastric antrum/cardia. pale/neutral in color w/ well-definied borders b/t cells
pyloric metaplasia classically occurs in terminal ileum in Crohn disease
Paneth cell metaplasia may rarely be seen in “backwash ileitis” of severe ulcerative colitis
activity (acute inflammaiton) w/ cryptitis and crypt abscess seen in acute self-limited colitis.
neutrophils have faint pink cytoplasmic halo
crohn disease: transmural inflammation with lymphoid aggregates
granuloma in crohn disease
combing fat crohns disease (mesenteric fat extends to serosal surface)
acute self-limited colitis.
No features of chronicity (no architectural distortion, no paneth cell metaplasia, no MM hypertorohy) to distinguish from IBD. Presence of chronic infammatory cells is not a feature of chronicity
correlate w/ stool culture to exclude infection
C. diff colitis
clue: epithelial cells fall of into lumen (due to C. diff toxin)
Gross path: pseudomembranes (fibrin, mucin, neutrophils)
ischemia involving mucosa: hyalinization of lamina propria (pink), withered cypts, hemorrhage
best way to asses hemorrhage is presence of hemosiderin laden macrophages!
pseudomembranes (fibrin, inflammatory cells) in ischemia
chronic ischmiea w/ inc. fibrosis (trichrome stain)
congenital anamolies of pancreas
o Accessory (ectopic pancreas): pancreatic tissue outside it’s normal location (often in stomach, small intestine, meckel’s diverticulum)
o Annular pancreas: abnormal ring of pancreas that encircles the duodenum; assoc w/ down’s syndrome
o Pancreas divisum: failure of dorsal and ventral buds/ducts to fuse leading to retention of 2 separate duct systems; duct of santorinin provides main drainagel may cause acute pancreatitis
