Acute & Chronic inflammation

Acute inflammation is an immediate response to injury or
infection that can cause
redness, heat, swelling, pain, and loss of function.
•• Hemodynamic changes in acute inflammation are
mediated by vasoactive
chemicals and, after a transient initial vasoconstriction,
produce massive dilation
with increased vascular permeability.
•• Neutrophils are important WBCs in acute inflammation;
they contain granules
with many degradative enzymes.

•• Acute inflammation may result in tissue regeneration,
scarring, abscess formation,or Chronic inflammation.
•• Cells important in chronic inflammation include
macrophages, lymphocytes,
eosinophils, and basophils.
•• Chronic granulomatous inflammation is a specialized form
of chronic
inflammation with modified macrophages (epithelioid cells
and multinucleated
giant cells) usually surrounded by a rim of lymphocytes. A
wide variety of
diseases can cause chronic granulomatous inflammation,
most notably TB,
syphilis, leprosy, and fungal infections.

Gastrointestinal Tract Pathology

ESOPHAGUS
• Histology
• The wall of the esophagus consists of four
layers: mucosa, submucosa, muscularis propria,
and adventitia. Unlike other areas of the GI tract,
the esophagus does not have a distinct serosal
covering.
• Mucosa: epithelium, lamina propria and
muscularis mucosaeEpithelium: nonkeratinized
stratified squamous epithelium

Congenital and Mechanical Disorders
1-Tracheoesophageal fistula may arise as a congenital
connection between the esophagus and trachea that is often
associated with esophageal atresia. It is often discovered
soon after birth because of aspiration. In adults the condition can
occur secondary to malignancy, trauma, or iatrogenic causes.
2-Esophageal webs are web-like protrusions of the esophageal
mucosa into the lumen which typically present with dysphagia.
3-Achalasia is a failure of the lower esophageal sphincter (LES)
to relax with swallowing.The etiology is unknown in most cases;
in South America, achalasia may be caused by Chagas disease.
Presentation is with progressive dysphagia. The esophagusis
characteristically dilated proximal to the lower esophageal
sphincter. Microscopically, there is a loss of ganglion cellsin the
myenteric plexus.

Hematemesis and Esophageal Bleeding
1-Mallory-Weiss syndrome is esophageal bleeding due to linear lacerations at the
gastroesophageal junction from severe prolonged vomiting; the most common cause
is acute alcohol ingestion and/or chronic alcoholism.
2-Esophageal varices are dilated submucosal veins in the lower third of the
esophagus, usually secondary to portal hypertension. The most common cause is
cirrhosis.
Both Mallory-Weiss tears and esophageal varices are associated with alcohol abuse
and can present with hematemesis.

Esophagitis
1-Gastroesophageal reflux disease (reflux esophagitis)
is esophageal irritation and inflammation due to reflux of gastric secretions into
the esophagus
2-Barrett esophagus
is a metaplasia of the squamous esophageal mucosa to a more protective
columnar type (intestinal metaplasia). It occurs because of chronic exposure to
gastric secretions. Barrett has an increased risk for dysplasia and esophageal
adenocarcinoma.

Cancer definition
In biology, cancer is defined as the malignant growth due
to uncontrolled cell division. It is now used as a general
term for over a hundred diseases characterized by
the uncontrolled, abnormal growth of cells. At advanced
stages, the cells spread (metastasis) locally or through the
blood or lymphatics.

What are Carcinoma
Carcinomas are cancers or
malignancies that begin in the
epithelial cells

Carcinoma in situ
The neoplastic cells does not penetrate the
Basement membrane.

Esophageal Carcinoma
• Squamous cell carcinoma
(SCC) of the esophagus is the most common
type of esophageal cancer in the world. It
affects males more than females; typical age is
usually age >50. Risk factors include:
• Heavy smoking and alcohol use
• Achalasia
• Diagnosis is by endoscopy with biopsy.

SCC OF ESOPHAGUS
The normal squamous epithelium at the left merges into the squamous cell
carcinoma at the right, which is infiltrating downward. The neoplastic squamous cells
are still similar to the normal squamous cells, but are less orderly. This is a well-
differentiated squamous cell carcinoma, because the neoplastic cells still have many
features of the squamous cell of origin

a malignant tumour formed from
glandular structures in epithelial
tissue..
Adenocarcinoma

Adenocarcinoma of the esophagus
-It arises in the distal esophagus.
-The progression from Barrett metaplasia to
dysplasia and eventually to invasive carcinoma
-occurs due to the stepwise accumulation
of genetic and epigenetic changes.
-The prognosis is poor.

STOMACH

Regions of the Stomach
The stomach has four regions.
1- The cardiac region, which is near the heart, surrounds
the lower esophageal sphincter where food enters the
stomach.
2-The fundic region, which holds food temporarily, is an
expanded portion superior to the cardiac region.
3-The body region, which comes next, is the main part.
4-The pyloric region narrows to become the pyloric canal
leading to the pyloric sphincter through which food enters
the duodenum, the first part of the small intestine.

Acute Inflammation and Stress Ulcers
-Acute hemorrhagic gastritis
.causes acute inflammation, erosion, and hemorrhage of the
gastric mucosa,
. secondary to a breakdown of the mucosal barrier and
acidinduced injury.
.The etiology is diverse, with initiating agents including
chronic aspirin or NSAID use, alcohol use, smoking, recent
surgery, burns, ischemia, stress,
uremia, and chemotherapy.
Patients present with epigastric abdominal pain, or with
gastric hemorrhage, hematemesis, and melena.

Gastric stress ulcers
--are multiple, small, round, superficial ulcers
of the stomach and duodenum.
- Predisposing factors include:
• NSAID use
• Severe stress
• Sepsis
• Shock
• Severe burn or trauma
• Elevated intracranial pressure (Cushing
ulcers)

Chronic Gastritis
Chronic gastritis is chronic
inflammation of the gastric mucosa,
eventually leading
to atrophy (chronic atrophic gastritis).
•

1- Fundic type chronic gastritis
-an autoimmune atrophic gastritis
. It is caused by autoantibodies directed against parietal cells
and/or intrinsic factor.
- The result is loss of parietal cells, decreased acid secretion,
increased serum gastrin (G-cell hyperplasia), and pernicious
anemia (megaloblastic anemia due to lack of intrinsic factor
and B12 malabsorption).
- Women are affected
more than men.
. Microscopically,
mucosal atrophy is seen with loss of glands and parietal cells,
chronic lymphoplasmacytic inflammation, and intestinal
metaplasia. --.Patients are at increased risk for
gastric carcinoma.

Antral type chronic gastritis (also called
Helicobacter pylori gastritis)
-is the most common form of chronic gastritis
--. The H. pylori organisms are curved, gram-negative rods
which produce urease.
- The risk of infection increases
with age.
- Infection is also associated with duodenal/gastric peptic
ulcer, and gastric
carcinoma with intestinal type histology.
Microscopically, H. pylori organisms are visible in the mucous
layer of the surface
epithelium. Other microscopic features include foci of acute
inflammation, chronic
inflammation with lymphoid follicles, and intestinal
metaplasia.

Chronic Peptic Ulcer (Benign Ulcer)
• Gastric peptic ulcers
• are associated with H. pylori (75%).
• Most are located in the lesser
curvature of the antrum.
• Grossly
• they are small (<3 cm), sharply
demarcated
• solitary with round/oval shape,
smooth borders, and radiating
• mucosal folds.
• Duodenal peptic ulcers
are more common than gastric
peptic ulcers.
• Associations include the following:
• • H. pylori (~100%)
• • Increased gastric acid secretion
• • Increased rate of gastric emptying
• • Blood group O
• • Multiple endocrine neoplasia
(MEN) type I
• • Zollinger-Ellison syndrome
• • Cirrhosis
• • Chronic obstructive pulmonary
disease
• Most duodenal peptic ulcers are
located in the anterior wall of the
proximal duodenum.

Gastric Carcinoma (Malignant Ulcer)
Risk factors;
- Dietary factors , Smoked fish and meats
- H. pylori infection
- chronic atrophic gastritis,
- smoking,
- blood type A

Macroscopical features.
-Most gastric carcinomas are located in the lesser
curvature of the antrum.
-They are large (>3 cm) ulcers with heaped-up
margins and a necrotic ulcer base.
- They may also occur as a flat or polypoid mass.

Histological types
• The intestinal type
shows gland-forming adenocarcinoma microscopically.
• The diffuse type shows diffuse infiltration of stomach by
poorly differentiated tumor cells, numerous signet-ring cells
(whose nuclei are displaced to
the periphery by intracellular mucin), and linitis plastica
(thickened “leather
bottle”–like stomach) gross appearance.

-Gastric carcinoma may specifically
metastasize to the left
supraclavicular lymph
node (Virchow sentinel node) and
to the ovary (Krukenberg tumor).
Diagnosis is by endoscopy with
biopsy; treatment is gastrectomy.
The prognosis is
poor, with overall 5-year survival
~30%.

GASTRIC LYMPHOMA
Marginal zone B-cell
lymphoma and diffuse
large B-cell lymphoma
occur in the
stomach.