failure of the cloacal diaphragm to involute

most common form of congenital intestinal atresia

"developmental rest" most frequently found in the upper third of the esophagus, referred to as an inlet patch

acid released from tissue can result in dysphagia, esophagitis, Barrett esophagus or adenocarcinoma

uncommon "developmental rest"

pancreatic tissue found in esophagus or stomach

small patches of ectopic gastric mucosa in the small bowel or colon

may present with occult blood loss due to peptic ulceration of adjacent tissue

failed involution of the vitelline duct, which connects the lumen of the gut to the yolk sac

occurs in the ileum

wall of pouch includes mucosa, submucosa, and muscularis propria

2% of population, w/in 2 ft of ileocecal valve, ~2 in long, 2x as common in males, symptomatic by age 2

present in second to third week of life as new-onset regurgitation and persistent, projectile, nonbilious vomiting

hyperperistalsis and a firm, ovoid abdominal mass is present

stem from hyperplasia of the pyloric muscularis propria

Hirschsprung disease

(congenital aganglionic megacolon)

due to a lack of migration or destruction of neural crest cells from cecum to rectum; aganglionosis

distal intestinal segment lacks both the Meissner submucosal and the Auerbach myenteric plexus 

heterozygous LOF mutation in RET

rectum is always affected; proximal colon becomes massively distended (megacolon)

clinically, presents as failure to pass meconium

Zenker diverticulum - above upper esophageal sphincter

Traction diverticulum - near midpoint of the esophagus

Epiphrenic diverticulum - above lower esophageal sphincter

Locate the following diverticula:

Zenker

Traction

Epiphrenic

occurs when outer longitudinal layer of smooth muscle contracts before the inner circular layer of smooth muscle

can cause periodic short-lived esophageal obstruction

uncommon ledge-like protrusion of esophageal mucosa that may cause obstruction

most common in women over 40

often assoc. w/ GE reflux, chronic GVH disease, or blistering skin diseases; causes dysphagia

most common in upper esophagus

generally semicircumferential, eccentric; composed of fibrovascular connective tissue and overlying epithelium

Esophageal rings

(Schatzki rings)

similar to esophageal webs but circumferential and thicker

above GE junction = A rings; squamous epithelium

Squamocolumnar junction of lower esophagus = B rings; gastric cardia-type mucosa

characterized by the triad of incomplete LES relaxation, increased LES tone, aperistalsis of the esophagus

caused by failure of distal esophageal inhibitory neurons or degenerative changes of vagus nerve or dorsal motor nucleus of the vagus

 *LES = lower esophageal sphincter

incomplete LES relaxation, increased LES tone, aperistalsis of the esophagus

longitudinal tears in the esophagus near the GE junction

often due to severe retching or vomiting secondary to alcohol intoxication

usually cross the GE junction

distal esophageal rupture of tears and mediastinitis = Boerhaave syndrome

damage or complication of pre-existing esophageal ulcer --> oral bacteria frequently found in ulcer bed -->

pathogenic organisms may invade the lamina

Candidiasis fungus = adherent, gray-white pseudomembranes composed of densely matted fungal hypae and inflammatory cells covering the esophageal mucosa 

inflammation of the esophagus

causes punched-out ulcers; nuclear viral inclusions within a rim of degenerative epithelium

dx by virus-specific antigens on immunostain

complication of allogeneic tissue transplant

esophagitis with basal epithelial cell apoptosis, mucosal atrophy, and submucosal fibrosis without significant inflammatory infiltrates

inflammatory condition of the esophagus often assoc. w/ GERD

simple hyperemia in mild cases

severe cases = eosinophils, then neutrophils recruited into squamous mucosa; basal zone hyperplasia exceeding 20% of the epithelial thickness and elongation of lamina propria papillae

present w/ dysphagia, heartburn, regurgitation of sour-tasting gastric contents

separation of the diaphragmatic crura and protrusion of the stomach into the thorax through the resulting gap

asymptomatic in most cases

10% symptomatic: heartburn, regurgitation of gastic juices

inflammatory infection of the esophagus

large number of intraepithelial eosinophils, particularly superficially

usually occurs in atopic individuals (lots of allergies)

symptoms: food impaction and dysphagia in adults; feeding intolerance or GERD-like symptoms in kids

failure of high-dose proton pump inhibitor tx and abscence of acid reflux are diagnostic

tx is restriction of food allergens

complication of chronic GERD; intestinal metaplasia within the esophageal squamous mucosa

confers an increased risk of esophageal adenocarcinoma

one or several tongues or patches of red, velvety mucosa extending upward from the GE junction

alternates with residual smooth, pale squamous mucosa, interface with light-brown columnar mucosa distally

categorized as long segment or short segment:

long segment = 3 cm or more; short segment = < 3 cm

goblet cells (defines intestinal metaplasia) are necessary for dx

increased epithelial proliferation; often assoc. w/ Barrett esophagus

atypical mitoses

nuclear hyperchromasia and stratification

irregularly clumped chromatin

increased nuclear to cytoplasmic ration

failure of epithelial cells to mature during migration to esophageal surface

abnormal glandular architecture, characterized by budding, irregular shapes, and cellular crowding

can be low or high grade

development of a congested subepithelial and submucosal venous plexus within the distal esophagus due to portal hypertension

usually assoc. w/ alcoholic liver disease or hepatic schistomiasis

torturous dilated veins with intact overlying mucosa

rupture causes overlying mucosa to appear ulcerated and necrotic; can lead to massive hematemesis

up to 50% of pts die from the first bleeding episode

survivors have a 50% chance of repeat hemorrhage within 1 year

esophageal cancer of white males with history of Barrett esophagus and GERD

occurs in the distal third of the esophagus; may invade adjacent gastric cardia

p53 mutations at early stages; additional mutations accumulate (c-ERB-B2, cyklin D1, cyclin E, RB, p16/INK4a)

initally a flat or raised patch in intact mucosa

may infiltrate diffusely or ulcerate to invade deeply

tumor produces mucin and back-to-back glands 

less frequently, signet-ring cells may be present

pain or difficulty swallowing, progressive weight loss, hematemesis, chest pain, vomiting

metastasize to gastric & celiac nodes (for distal third)

esophageal cancer of black men; more common world wide

occur in middle third of esophagus

loss of p53 and p16/INK4a

begins as nests of squamous dysplasia

early small gray-white plaque-like thickenings grow into tumors masses (polypoid or exophytic) that protrude into the lumen; moderately to well differentiated

commonly causes strictures

spread is via mediastinal, paratracheal, and tracheobronchial nodes (for middle third)

dysphagia, odynophagia, obstruction, weight loss

transient mucosal inflammatory process of stomach

epigastric pain, nausea, vomiting

may be due to reduced mucin synthesis in elderly, NSAID use, H. pylori, direct cellular injury, cell hypoxia

lamina propria shows only moderate edema and slight vascular congestion; surface epithelium is intact

neutrophilic invasion of the epithelium; superficial epithelial sloughing (erosion); fibrinous luminal exudate

stomach lesions with variable depth of erosion, rounded, <1 cm

base is stained brown to black by acid digestion of extravasated blood; may be assoc. w/ transmural inflammation and local serositis

found anywhere in the stomach, often multiple

no scarring or thickening of blood vessels

recovery can be complete with correction and without complications

most common cause of chronic gastritis; localized to antrum

gastric biposy = Gm(-) spiral-shaped or curved bacilli

concentrates in superficial mucus

antral mucosa is erythematous with a coarse or nodular appearance; neutrophil-created pit abscesses 

intraepithelial neutrophils and subepithelial plasma cells

lymphoid aggregates indicate mucosa-associated lymphoid tissue (MALT)= potential for lymphoma

dx by serology, fecal bacterial detection, or urea breath test

spiral-shaped or curved bacilli seen in duodenal ulcers and chronic gastritis

virulence due to:

flagella (allows bacteria to be motile in viscous mucus), urease (generates ammonia, elevating local pH), adhesins (enhances bacterial adherence to surface foveolar cells), and toxins (cytotoxin-associated gene A, CagA)

form of chronic gastritis

antibodies to parietal cells and intrinsic factor, reduced pepsinogen I concentration, antral endocrine cell hyperplasia, vitamin B₁₂ deficiency, achlorhydria

hypergastrinemia, G cell hyperplasia, pernicious anemia, chief cell destruction

damage of the oxyntic (acid-producing) mucosa in the body and fundus

with diffuse atrophy, oxyntic mucosa is thinned and rugal folds are lost

with pernicious anemia, nuclear enlargement in epithelial cells

lymphocyte, macrophage, plasma cell infiltrate

antral endocrine hyperplasia; surface elevations correlate w/ intestinal metaplasia (goblet cells)

often associated with other autoimmune disorders, but no linkage to any HLA alleles

clinical picture is usually dominated by anemic symptoms; B₁₂ deficiency causes atrophic glossitis (smooth, beefy tongue), epithelial megaloblastosis, malabsorptive diarrhea, and peripheral neuropathy

highest risk for adenocarcinoma

uncommon gastritis marked by foveolar hyperplasia, glandular regenerative changes, mucosal edema neutrophils are NOT abundant

causes: chemical injury, NSAID use, bile reflux, mucosal trauma secondary to prolapse

gastric antral vascular ectasia (GAVE) in antral trauma = longitudinal stripes of edematous erythematous mucosa alternating with less severely injured mucosa (watermelon stomach)

antral mucosa shows dilated capillaries with fibrin thrombi

uncommon form of gastritis characterized by tissue damage w/ dense infiltrates of eosinophils in the mucosa and muscularis

usually in antrum or pylorus

peripheral eosinophilia, increased serum IgE levels

allergic reactions or parasitic infections

gastritis w/ nonspecific symptoms (abd pain, anorexia, nausea, vomiting) that usually affects women

often assoc. w/ celiac disease

thickened folds covered by small nodules with central aphthous ulceration (varioliform gastritis)

affects entire stomach

marked increase in intraepithelial T lymphocytes, mostly CD8+ cells

any gastritis that contains granulomas or aggregates of epithelioid histiocytes

usually caused by Crohn disease or Sarcoidosis

narrowing and rigidity of the gastric antrum may occur secondary to transmural granulomatous inflammation

exuberant reactive epithelial proliferation assoc. w/ entrapment of epithelial-lined cysts in layer of the gastric wall

cysts in submucosa = polyposa variant

 cysts in deeper layers = profunda variant

believed to be trauma-induced due to association with chronic gastritis and partial gastrectomy

hypertrophic gastropathy caused by excessive secretion of TGF-α

diffuse hyperplasia of foveolar mucous cells of body and fundus

glands are elongated with corkscrew appearance

irregular enlargement of gastric rugae

hypoproteinemia, weight loss, diarrhea, peripheral edema

in peds pts, usually self-limited after respiratory infxn

tx is supportive: IV albumin, parenteral nutrition

caused by gastrin-secreting tumors (gastrinomas)

most common in small intestine and pancreas

present with duodenal ulcers or chronic diarrhea

doubling of oxyntic mucosal thickness due to fivefold increase in parietal cell number

hyperplasia of mucous neck cells, mucin hyperproduction, proliferation of endocrine cells

60-90% of gastrinomas are malignant

neutrophil infiltrate; risk of MEN

polyps that usually develop with chronic gastritis; aacount for 75% of gasric polyps

common between 50 and 60 yrs

smaller than 1 cm, often multiple

polyps are ovoid in shape with smooth surface

irregular, cystically dilated, and elongated foveolar glands

lamina propria is edematous with variable degrees of inflammation

often develop in assoc. w/ FAP

believed to be due to increased gastric secretion followed by glandular hyperplasia

more common in women, avg age = 50

variable degree of symptoms: none to nonspecific

in gastric body and fundus

well circumscribed lesions with smooth surface

single or multiple

cystically dilated, irregular glands lined by flattened parietal and chief cells

tumors with background of chronic gastritis with atrophy and intestinal metaplasia

men, between 50-60

soliltary, less than 2 cm, usually in the antrum

composed of intestinal-type columnar epithelium

low or high grade epithelial dysplasia

enlargement, elongation, and hyperchromasia of nuclei, epithelial crowding, pseudostratification

high grade = atypia, irregular architecture (glandular budding, gland-within-gland, cribiform)

most common stomach malignancy

most common along antrum and lesser curvature

dyspepsia, dysphagia, nausea, weight loss, anorexia, anemia, alterered bowl habits, hemorrhage

assoc. w/ loss of E-cadherin (CDH1)

intestinal morphology = bulky tumor w/ glandular structures; heaped up borders with central ulceration; gland formation; broad cohesive front

diffuse infiltrative pattern = signet-ring cells, discohesive cells without gland formation, desmoplastic reaction, diffuse rugal flattening and rigid, thickened wall (leather bottle appearance, "linitis plastica")

mucin lakes in both morphologies 

assoc. w/ H. pylori infection; assoc. w/ t(11;18)(q21q21), t(1;14)(p22q32), and t(14;18)(q32;q21) all leading to constitutive activation of NF-κB

dense lymphocytic infiltrate in lamina propria

infiltrate the gastric glands focally to create diagnostic lymphoepithelial lesions

accumulation of large amts of pale cytoplasm ("monocytoid" change)

express B cell markers CD19 and CD20

present with dyspepsia, epigastric pain, hematemesis, melena, weight loss

well-differentiated neuroendocrine carcinoma of the GI tract; 40% occur in small intestine

intramural or submucosal masses that create small polypoid lesions

tend to be yellow or tan in color and are very firm due to intense desmoplastic reaction

composed of islands, trabeculae, strands, glands, or sheets or uniform cells with scant, pink granular cytoplasms and a round to oval stippled nucleus (salt and pepper pattern)

immunostains positive for synaptophysin, chromogranin A

symptoms determined by hormones secreted

midgut are the most aggressive

mesenchymal tumor of the stomach

some related to Carney triad

more common in men with peak age of 60

solitary, well-circumscribed fleshy mass covered by ulcerated or intact mucosa

spindle type - composed of thin elongated cells

epithelioid type - epithelioid appearing cells

immunostain positive for c-KIT

often present with anemia; tx w/ imatinib

nonhereditary syndrome seen primarily in young females 

includes GIST, paraganglioma, and pulmonary chondroma; increased incidence of NF-1

viral inflammation of the esophagus

shallow ulceration; nuclear and cytoplasmic inclusions within capillary endothelium and stromal cells

dx by virus-specific antigens on immuno stain

disease assoc. w/ H. pylori-induced hyperchlorhydric chronic gastritis

imbalance of mucosal defense and damaging forces

mucosa adjacent to ulcers is abnormal

most common in gastric antrum and first part of duodenum (4x more common in duodenum)

higher risk for males

underlying causes are believed to be H. Pylori and NSAID use

round to oval punched-out defect level with the surrounding mucosa

hemorrhage and fibrin deposition are present on the gastric serosa

perforation = free air under diaphragm on radiograph

base of ulcers are smooth and clean underlaid by a neutrophilic inflammatory infiltrate; beneath this, active granulation tissue infiltrated with mononuclear leukocytes and fibrous/collagenous scar

thickened vessels walls within scarred area

clinically, epigastric burning or aching pain that tends to occur 1-3 hours after meals during the day, is worse at night, and relieved by alkali or food

syndrome associated w/ ileal carcinoid tumor

cutaneous flushing, sweating, bronchospasm, colicky abdominal pain, diarrhea, and right-sided cardiac valvular fibrosis

cause by vasoactive substances secreted by the tumor into the systemic circulation