Gastrointestinal Tract

1
Gastrointestinal Tract
2
Gastrointestinal Tract
3

• Stomach
• Glands
• Parietal cells found in fundus and body
• Secrete HCl intrinsic factor
• Chief cells are more at fundus and body
• Secrete pepsinogen I II
• Congenital Anomalies
• 1. Diaphragmatic Hernia
• A defect in the diaphragm ? away from the hiatal
  orifice (not hiatal hernia)
• Portions of stomach small intestine herniates
• Results in respiratory impairment pulmonary
  hypoplasia

4
Stomach - Normal
IF
5
Stomach - Normal
6

• Stomach
• . 2. Congenital Hypertrophic Pyloric Stenosis
• Hypertrophy of the circular muscle of the pylorus
• Results in Regurgitation vomiting in the
  neonatal period
• VGP-visible Gastric peristalsis palpable mass
  in the epigastrium
• males, multifactorial inheritance.
• Rx A full thickness muscle splitting incision
  (pyloro-myotomy) is curative (Hellers operation)

7
Stomach - Normal
normal fundus
esophagus
antrum ( pylorus) emptying into the 1ST of
duodenum
8

• Stomach
• Acute Gastritis inflammation of gastric mucosa
• acute presence of neutrophils
• Chronic lymphocytes and plasma cells
• Caused by ingestion of strong acids or alkalies,
  NSAIDs, cancer chemotherapy, irradiation,
  alcohol, uremia, severe stress shock states
• Proposed mechanisms ? acid production with ?
  surface bicarbonate buffer
• Morphology Mucosal edema, hyperemia, PML
  infiltration, erosions (not deeper than
  muscularis mucosa) hemorrhages

9
Acute Gastritis

• Gastric mucosa demonstrates infiltration by
  Neutrophils

10
Acute Gastritis

• diffusely hyperemic gastric mucosa
• causes for acute gastritis
• alcoholism
• drugs
• infections, etc.

11

• Stomach
• Chronic Gastritis Chronic mucosal inflammation
• Leading to mucosal atrophy, intestinal metaplasia
  dysplasia.
• Pathogenesis
• Chronic infection by Helicobacter pylori (90)
  MCC of chronic gastritis, Elaboration of urease ?
  produces ammonia that buffers gastric acid,
  protecting organism from acid
• Other diseases associated with H. pylori
  Infection
• Peptic ulcer disease
• Gastric carcinoma
• Gastric lymphoma
• Autoimmunity (gt10) Antibodies to parietal cells
  cause parietal cell destruction (HCl intrinsic
  factor)

12

• Stomach
• Chronic Gastritis
• Morphology
• Autoimmune ? diffuse mucosal damage of the
  body-fundic mucosa
• H. pylori ?affect antral mucosa
• Histology Lymphocytic plasma cell infiltrate
  of the lamina propria
• atrophy, regeneration, metaplasia (to intestinal
  type mucosa) dysplasia.
• H. pylori detected on the mucosal surface
• Clinically
• Mild abdominal discomfort, nausea, vomiting
  hypochlorhydria, hypergastrinemia rarely
• Overt pernicious anemia (in autoimmune)
  gastritis).
• Long-term risk of cancer is 2-4

13
H. pylori

• small curved to spiral rod-shaped bacterium is
  found in the surface epithelial mucus of most
  patients with active gastritis
• The rods are seen here with a methylene blue
  stain.

14
Autoimmune gastritis

• Autoimmune gastritis - pernicious anemia
• Chronic atrophic gastritis is associated with
  Abs
• - intrinsic factor
• - patietal cell
• bright green IF- in the parietal cells of the
  gastric mucosa.

15

• Stomach
• Peptic Ulcer Disease
• Ulcer - a breach in mucosa extends thru
  muscularis mucosae into submucosa or deeper
• 1) Acute Gastric Ulcers
• acute erosive gastritis erosions ABOVE the
  muscularis mucosa
• Caused by Severe stress ( Stress Ulcers)
• Shock, extensive burns (Curlings ulcers)
• Severe head injuries (Cushings ulcers)
• patients in Intensive Care Units, use of NSAIDs.
• Morphology Multiple, small (lt1 cm) ulcers,
  normal adjacent mucosa
• Clinically Upper GIT hemorrhage.
• Treatment treat underlying cause

16
Stress ulcers

• small, shallow gastric ulcerations known as
  "stress ulcers"
• patients with a variety of stressful conditions,
  including trauma, burns, sepsis, and shock.
• Anti-inflammatory drugs such as aspirin and
  NSAIDs may play a role in their appearance.

17

• 2) Peptic ulcers - chronic
• Characterized by Solitary, chronic ulcers,
• Ratio of duodenal gastric 4 1 (Duodenal
  ulcer is more common)
• Morphology Sharply punched out mucosal defect
  With sharp borders clean ulcer base.
• Surrounding mucosa shows chronic gastritis
  radial convergence of rugal folds towards the
  ulcer niche (unlike malignant ulcer)
• Clinically Epigastric pain 1-3 hours after meals
  worse at night nausea vomiting belching
  occult blood in the stools.
• Complications
• Perforation - accounts for 2/3rds of ulcer
  deaths
• Hemorrhage - accounts for 25 of ulcer deaths
• Obstruction - causes severe crampy abdominal pain
  
• Malignant transformation is extremely rare

18
Peptic Ulcerpathogenesis
19
Gastric ulcer

• larger 3 x 4 cm gastric ulcer
• This ulcer is much deeper with more irregular
  margins
• Complications of gastric ulcers (either benign or
  malignant) include
• pain
• Bleeding (MC)
• Perforation (most dangerous)
• obstruction.

20
Gastric ulcer

• Microscopically
• the ulcer here is sharply demarcated, with normal
  gastric mucosa on the left falling away into a
  deep ulcer whose base contains inflamed, necrotic
  debris
• Arterial branch at the ulcer base is eroded and
  bleeding.

21

• 3). Hypertrophic Gastropathy
• Characterized by Giant enlargement of the gastric
  rugal folds
• Caused by hyperplasia of epithelial cells ( not
  due to inflammation )
• ?risk of cancer
• Includes 3 variants
• A) Menetriers disease
• Hyperplasia of surface mucous cells
• glandular atrophy
• excessive loss of proteins in gastric secretion
  (protein-losing Gastropathy)
• B) Hypersecretory Gastropathy
• Hyperplasia of parietal and chief cells
• Secondary to excessive gastrin stimulation.
• C) Zollinger - Ellison Syndrome
• Caused by Gastrinoma of Pancreas secreting
  gastrin ? elevated serum gastrin levels
• multiple peptic ulcerations in stomach, duodenum,
  jejunum
• Hypertrophic rugal folds Parietal cell
  hyperplasia ? excess gastric acid production

22

• Benign Tumors of the stomach
• 1) Gastric polyps
• Most of the polyps ( 90) are non-neoplastic
  polyps
• (hyperplastic /or inflammatory)
• no malignant potential.
• Gastric polyps must be biopsied
• 2) Adenomatous Polyps
• true neoplasms with proliferative dysplastic
  epithelium
• Have malignant potential, common in old age
• MC associated with chronic gastritis or familial
  polyposis syndromes

23

• Malignant - Tumors
• 1. Gastric Carcinoma
• Incidence 4-fold decline in incidence over the
  last 70 years (for unknown reasons).
• Risk Factors
• Diet Nitrites (from food preservatives), smoked
  and salted foods, deficiency of fresh fruits and
  vegetables.
• Host Factors Chronic gastritis (autoimmune H.
  pylori), Adenomatous polyps, partial gastrectomy
  pts.
• Genetic Factors blood group A, close relatives
  of stomach cancer patients, certain racial groups
  (Japanese)
• Classification
• A) Early Gastric Carcinoma Confined to the
  mucosa submucosa, despite lymph node spread
• Associated with very good prognosis (gt90 5-year
  survival)

24

• B) Advanced Gastric Carcinoma Has extended
  beyond the submucosa Spread is by local
  invasion, lymphatics, blood (to liver lungs)
• Krukenberg tumor bilateral ovarian metastases
  (stomach, breast, pancreas, and even gallbladder
  )
• Virchow node left supraclavicular node with
  mets.
• Sister Mary Joseph nodule metastasize to the
  periumbilical region (subcutaneous malignant
  nodule)
• Histologic types
• Intestinal type, glandular, expansile growth
  pattern
• Gastric type, diffuse signet ring infiltrating
  pattern
• Pathologic stage is the most important prognostic
  indicator
• 2) Gastrointestinal Stromal Tumor (GISTs)
• Arise from Interstitial cells of Cajal
• c-KIT (CD117) CD34- positive

25

• 3. Carcinoid (neuroendocrine) tumors
• made of Enterochromaffin-like (ECL) cell tumors
• Associated with multiple endocrine neoplasia type
  1 (MEN1) Zollinger-Ellison syndromes
• 4) Gastric Lymphoma
• MC site for extranodal lymphoma
• majority (gt80) are associated with H. pylori
  chronic gastritis

26
Stomach gastric carcinoma

• Gastric adenocarcinoma in the U.S., most gastric
  cancers are discovered at a late stage when the
  neoplasm has invaded and/or metastasized.
• All gastric ulcers and All gastric masses must
  be biopsied,
• In contrast, virtually all duodenal peptic ulcers
  are benign.

27
Stomach gastric carcinoma

• Malignant gastric ulcer
• This ulcer on biopsy proved to be malignant, so
  the stomach was resected

28

• Linitis plastica
• a diffuse infiltrative gastric adenocarcinoma
• stomach looks like a shrunken "leather bottle"
  appearance
• markedly thickened gastric wall
• very poor prognosis.

29
Case - 1

• A 48-year-old man has had vague abdominal
  discomfort for a number of years. There is no
  history of hematemesis, but he has occasional
  nausea and vomiting. An upper GI endoscopy is
  performed. There is no evidence for ulceration or
  a mass lesion, and gastric biopsies are taken.
  Images 8.1 and 8.2 demonstrate the gastric mucosa
  at low and high magnification. The surface of the
  gastric mucosa at high magnification is seen in
  images 8.3 and 8.4.

30
1.1
31
1.2
32
1.3
33
1.4
34
Case - 2

• A 55-year-old woman, with a history of epigastric
  pain relieved by food, complained of episodes of
  hematemesis that have occurred in the past week.
  Upper GI endoscopy with biopsies was performed
  (image 3.1). The specimen shown here is from the
  subsequent partial gastrectomy (image 3.2). The
  lesion appears as a cup-shaped ulcer filled with
  blood clot. The ulcer, which was found to extend
  almost through the gastric wall, is lined by
  necrotic debris and acute inflammatory cells
  overlying a base of granulation tissue and
  fibrosis (images 3.3 and 3.4) with a large vessel
  at the base (image 3.5).

35
2.1
36
3.2
37
3.3
38
Case -3

• A 60-year-old man complained of anorexia,
  vomiting, and vague abdominal pain accompanied by
  weight loss of 15 kg over the past two months.
  Physical examination revealed supraclavicular
  lymphadenopathy. An abdominal CT scan revealed
  that the stomach wall was thickened . He became
  progressively cachectic and died. At autopsy, the
  stomach was diffusely thickened and leather-like
  . Microscopic sections of the gastric wall are
  shown .

39
3.1
40
3.2
41
3.3