Gastrointestinal System Dr.Nadwa S.Al-azow Assis.prof.pathology Department

The gastrointestinal (GI) tract is a hollow tube extending from the oral cavity to the anus that consists of anatomically distinct segments, including the esophagus, stomach, small intestine, colon, rectum, and anus

LEUKOPLAKIA a white patch or plaque that cannot be scraped off and cannot be characterized clinically or pathologically as any other disease Approximately 3% of the world's population have leukoplakic lesions, and somewhere between 5% and 25% of these lesions are premalignant

SALIVARY GLANDS There are three major salivary glands parotid, submandibular, and sublingual as well as innumerable minor salivary glands distributed throughout the mucosa of the oral cavity. All these glands are subject to inflammation or to the development of neoplasms.

Inflammation (Sialadenitis) Causes : Trumatic Viral (Mumps) Bacterial Autoimmune (Sjögren syndrome)

PLEOMORPHIC ADENOMA 60% of tumors in the parotid, are less common in the submandibular glands, and rarely in minor benign tumors that consist of a mixture of ductal (epithelial) and myoepithelial cells, and therefore they show both epithelial and mesenchymal differentiation. epithelial elements dispersed throughout the matrix along with varying degrees of myxoid, hyaline, chondroid (cartilaginous), and even osseous tissue

WARTHIN TUMOR (papillary cystadenoma lymphomatosum) almost exclusively in the parotid more commonly in males than in females, usually in the fifth to seventh decades of life. On microscopic examination cystic spaces are lined by a double layer of neoplastic epithelial cells resting on a dense lymphoid stroma

Adenoid cystic carcinoma uncommon tumor, which in approximately 50% of cases is found in the minor salivary glands , the major salivary glands affected are parotid & submandibular Microscopically: solid growth of small hyperchromatic neoplastic cells surrounding small (microcystic) spaces filled with mucinous secretions giving rise to cribriform appearance

CONGENITAL ANOMALIES ECTOPIC TISSUE (gastric, sebaceous, pancreatic)‏ Atresia/Fistula/Stenosis/”Webs” MOST COMMON

MOTOR DISORDERS Achalasia Hiatal Hernia (sliding [95%], paraesophageal)‏ “ZENKER” diverticulum Esophagophrenic diverticulum Mallory-Weiss tear

Achalasia Achalasia is a Greek term meaning ‘failure to relax’ is characterized by poor relaxation of the functional lower oesophageal sphincter. Causes: most of the cases is unknown ,but could be due to systemic sclerosis and South American trypanosomiasis (Chagas’ disease) may present at any stage in life, usually with dysphagia and regurgitation of undigested food material. Aspiration pneumonia is a significant problem Microscopically, the disease is characterized by a reduction in the numbers of neurones in the muscular (myenteric) plexus of the lower oesophagus, dilatation of proximal esophagus ,Inflammation &ulceration of mucosa .

Esophagitis: Inflammation of esophagial mucosa Causes: Reflux oesophagitis : refluxed gastroduodenal contents Infectious agents (Candida, herpes simplex virus) rarely in immunocompromised patient. The oesophagus may be involved in Crohn’s disease and in systemic sclerosis. Oesophageal obstruction (tumour, achalasia) leads to a secondary proximal oesophagitis.

Barrett Esophagus: characterized by intestinal metaplasia within the esophageal squamous mucosa 10% of individuals with symptomatic Gastroesophageal reflux diseases most common in white males and it typically presents between 40 and 60 years of age. The signifigance of it: an increased risk of esophageal adenocarcinoma.

ESOPHAGEAL VARICES development of a congested subepithelial and submucosal venous plexus within the distal esophagus. These vessels, termed varices, develop in 90% of cirrhotic patients, most commonly in association with alcoholic liver disease. Hepatic schistosomiasis is the second most common cause of varices. they may rupture, causing massive hematemesis half of the patients die from the first bleeding episode either as a direct consequence of hemorrhage or following hepatic coma triggered by hypovolemic shock.

Esophageal Tumors Benign Tumors Malignant tumors Surface epith.T. (Papilloma) Mesenchymal Leiomyoma,lipoma, Hemangioma….. Surface epith Squa.cell Ca. Adenocarcinoma Others: melanoma, Carcinoid sarcoma

Squamous Cell Carcinoma Arise from Sq.epithelium as exophytic, ulcerative masses that partly or almost totally occlude the lumen. Adenocarcinomas generally arise in Barrett’s oesophagus, this is a disease of Western society

Stomach Inflammation of the stomach (Gastritis) Acute chronic Gastric Tumors

If you think of the acid production in the stomach to be ONLY in the mid-BODY, and the proximal and distal ends as chiefly mucous to protect the esophagus and duodenum from the harsh acid, then you will understand the histology.

Acute Gastritis Pathogenesis: is a transient mucosal inflammatory process Pathogenesis: Acute or chronic gastritis can occur following disruption of any of these protective mechanisms Mucin secreted by surface foveolar cells forms a thin layer of mucus (defect occur as in elderly, bicarbonate ion secretion ( NSAI drugs reduce producti on), chemotherapy rich vascular supply Clinically: Mild cases the pt. presented with nausea, vomiting in severe cases causes bleeding

Microscopically : Mild condition show neutrophils infiltrated the surface epithelium & glands in lamina propria with lymphocytes and plasma chronic inflammatory cells In severe cases there are erosion of surface epithelium , ulceration , bleeding and hemorrhage.

ACUTE GASTRIC ULCERATION Stress ulcers are most common in individuals with shock, sepsis, or severe trauma Ulcers occurring in the proximal duodenum and associated with severe burns or trauma are called Curling ulcers. Gastric, duodenal, and esophageal ulcers arising in persons with intracranial disease are termed Cushing ulcers and carry a high incidence of perforation. Pathogenesis.

Acute gastritis: hyperemic erythmatous edematous gastric mucosa with foci of superficial erosions. There are many causes for acute gastritis: alcoholism, drugs, infections, etc

Chronic Gastritis Causes : The most common cause of chronic gastritis is infection with the bacillus Helicobacter pylori. Others : psychological stress, caffeine, alcohol, and tobacco . Autoimmune gastritis ( cause atrophic gastritis, 10%of chronic gastritis in the absence of H.pylori) Less common causes : radiation injury, chronic bile reflux, mechanical injury, and involvement by systemic disease such as Crohn disease, amyloidosis, or graft-versus-host disease.

HELICOBACTER PYLORI GASTRITIS spiral-shaped or curved bacilli Presented in almost all patients with duodenal ulcers and the majority of individuals with gastric ulcers or chronic gastritis. H. pylori has important roles in gastric and duodenal diseases.( peptic ulcer disease, increased risk of gastric cancer)

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

Pathogenesis. H.Pylori causes Antral gastritis with high acid secretion , progress to involve the fundic and body mucosa , in advanced untreated conditions lead to pangatritis associated with multifocal mucosal atrophy, reduced acid secretion, intestinal metaplasia, and increased risk of gastric adenocarcinoma.

Morphological Features of H.pylori asssociated chronic gastritis: H.Pylori is concentrated within the superficial mucus overlying epithelial cells in the surface and neck regions. H. pylori are typically found in the antrum , neutrophilic cells infiltration within the lamina propria In addition, the superficial lamina propria includes large numbers of plasma cells, often in clusters or sheets, and increased numbers of lymphocytes and macrophages.

PEPTIC ULCER DISEASE 85% -100% are duodenal ulcers 65% gastric ulcer Epidemiology. The imbalances of mucosal defenses and damaging forces that cause chronic gastritis are also responsible for PUD the main causes for hyperacidity: H.pylori, parietal cell hyperplasia, hypergastrinemia, …. Co-factors NSAIDrugs direct injury to the mucosa Smoking , alcohol consumption affect the blood supply of mucosa

Morphology: Duodenal ulcers involve the anterior duodenal wall. Gastric peptic ulcers are predominantly located along the lesser curvature near the interface of the body and antrum. 80% solitary ,round to oval, sharply punched-out defect, hang out the surrounding mucosa The base show fibrinoid material, Beneath this, active granulation tissue infiltrated with mononuclear leukocytes and a fibrous or collagenous scar

Complications of Peptic Ulcers: Bleeding Occurs in 15% to 20% of patients Most frequent complication May be life-threatening Accounts for 25% of ulcer deaths May be the first indication of an ulcer Perforation Occurs in about 5% of patients Accounts for two thirds of ulcer deaths Rarely, is the first indication of an ulcer Obstruction from edema or scarring Occurs in about 2% of patients Most often due to pyloric channel ulcers May also occur with duodenal ulcers Causes incapacitating, crampy abdominal pain Rarely, may lead to total obstruction with intractable vomiting Malignant transformation of peptic ulcers is very rare Would this slide be seen in a REAL classroom to those sitting in the back row?

GASTRIC TUMORS Gastro-Intestinal “Stromal” Tumor (GIST) BENIGN: “POLYPS*” (HYPERPLASTIC vs. ADENOMATOUS) LEIOMYOMAS LIPOMAS MALIGNANT (ADENO)-Carcinoma LYMPHOMA Others Gastro-Intestinal “Stromal” Tumor (GIST) CARCINOID (NEUROENDOCRINE) In general. A “polyp*” can be thought of as ANYTHING which projects as a bump or nodule from a mucosal surface. HYPERPLASTIC POLYPS are considered to be NON-neoplastic, and therefore NEVER turn into cancers. ADENOMATOUS polyps are true benign neoplasms and MAY turn into carcinomas, particularly if the exhibit DYSPLASIA on biopsy. This SAME general principle, is even MORE true of the colon! But in general, you know the drill: 1) Benign, 2) Malignant, and 1) epithelial, 2) stromal, and 3) lymphoid

RISK FACTORS H. Pylori Type of food : Nitrites, smoked meats, pickled, salted, chili peppers, Low Socioeconomic tobacco Chronic gastritis, Barrett’s, adenomas Family history

Morhophology: Adenocrcinoma Intestinal Type : Grossly : Exophytic , Nodular, ulcerative Excavaeted. Microscopically: glandular component of malignant cells. Diffuse type: Infitrative to gastric wall , malignant cells had intracellular mucin push the nucleus to the periphery (Linitis Plastica)

SMALL INTESTINE AND COLON The small intestine and colon account for the majority of GI tract length and are the sites of a broad array of diseases SI = 6 meters (100% intraP, except for duodenum), LI = 1.5 meters (50% retroP) Mucosa, submucosa, muscularis, serosa

Intestinal Obstruction small intestine is most often involved because of its relatively narrow lumen. Hernias, Intestinal adhesions, Intussusception Volvulus account for 80% of mechanical obstructions

PSEUDOMEMBRANOUS COLITIS caused by Clostridium difficile, is also known as antibiotic-associated colitis or antibiotic-associated diarrhea disruption of the normal colonic flora by antibiotics allows C. difficile overgrowth

Morphologically: formation ofpseudomembranes made up of an adherent layer of inflammatory cells and debris at sites of colonic mucosal injury. The surface epithelium is denuded, and the superficial lamina propria contains a dense infiltrate of neutrophils and occasional fibrin thrombi within capillaries. These exudates coalesce to form the pseudomembranes

INTRALUMINAL (PANCREATIC DEFECTIVE/REDUCED BILE Malabsorption: is defective in nutrient absorption , presents most commonly as chronic diarrhea, causes : INTRALUMINAL (PANCREATIC DEFECTIVE/REDUCED BILE BACTERIAL OVERGROWTH) Defect in the wall (defect in mucosal function , mucosal atrophy….) Out side the intestine( like adhesion , tumor outside)

CELIAC DISEASE Also called NON-tropical SPRUE Also called GLUTEN-SENSITIVE ENTEROPATHY Sensitivity to GLUTEN, a wheat protein, gliadin Immobilizes T-cells Also in oat, barley, rye The histopathology is characterized by increased numbers of intraepithelial CD8+ T lymphocytes (intraepithelial lymphocytosis), crypt hyperplasia, and villous atrophy . Relieved by gluten withdrawal

Inflammatory Bowel Diseases Crohn disease : affecting the small & large intestine ( oral to anus) mainly ileocecal region Ulcerative Colitis : only large intestine, sigmoid region

Ulcerative Colitis increased CANCER RISK Charcteristic Features : IDIOPATHIC DEVELOPED COUNTRIES COLONIC INFLAMMATION SIMILAR Rx Ulcerative Colitis increased CANCER RISK

Diverticulosis : acquired pseudo-diverticular outpouchings of the colonic mucosa and submucosa. rare in persons under age 30, but the prevalence approaches 50% in Western adult populations over age 60. Occur due to increased intraluminal pressure in the sigmoid , due to constipation (low fiber diet)

Complication Ulceration Bacterial infection & abscess formation Perforation & peritonitis Fistula formation (with bladder , vagina)

Intestinal Polyps : Non-neoplastic polyp Hyperplastic Polyp( seen in large bowel in Inflammatory disases as crohn’s disease or ulcerative colitis) Hamartomatous polyp : autosomal dominant inherited condition of Peutz– Jeghers syndrome, Neoplastic polyp: more common in the large than small bowel , about one-third of individuals at 70 years of age

The tubular adenoma: tubular crypts arising from a lobulated surface

The villous adenoma : less common type has a small intestine like velvety surface made up of numerous epithelial-lined projections .

FAMILIAL ADENOMATOUS POLYPOSIS (FAP) is an autosomal dominant disorder patients develop numerous colorectal adenomas as teenagers. It is caused by mutations of the adenomatous polyposis coli (APC) gene. 100-1000 in no.in the whole large bowel Colorectal adenocarcinoma develops in 100% of untreated FAP patients, often before age 30Y. total colectomy is Rx of choice to decrease the incidence of colon Ca.

Colorectal Carcinoma : Cancers of the large bowel are among the most common neoplasms in Western society Low fiber diet , high intake of refind carbohydrate &Fat. Low antioxidant Vit A,C,E (all had a role in developing adenocarcinoma of large bowel.

Pathogenesis : Two genetic pathways the APC/β-catenin pathway adenoma-carcinoma sequence microsatellite instability pathway, which is associated with defects in DNA mismatch repair

Morphology : About one-half are found in the rectum, a further one-third in the sigmoid, and the rest are spread equally across the remainder of the colon Tumors of proximal colon appear as exophytic or ulcerative mass rarely cause obstruction In distal part presented as annular lesion cause narrowing of lumen and obstruction . Tumors composed of glandular structures lined by malignant cells at different differentiation Some times signet ring ca. as in gastric Ca.

Many systems for staging of colorectal ca Many systems for staging of colorectal ca. one of them Dukes Staging System

ANAL CANAL CARCINOMAS MORE LIKELY TO BE SQUAMOUS, or “basaloid” WORSE IN PROGNOSIS HPV RELATED

THE APPENDIX is a normal true diverticulum of the cecum that is prone to acute and chronic inflammation Acute Appendicitis initiated by progressive increases in intraluminal pressure that compromise venous outflow. In 50% to 80% of cases, acute appendicitis is associated with overt luminal obstruction caused by stool (fecolith, oxyuriasis vermicularis (worm), tumor…) Microscopically: transmural infiltration of neutrophils with ulceration of linning mucosa

ACUTE APPENDICITIS What is the white junk coating the surface? Answer: FIBRIN

The presence of neutrophils invading the muscularis is the diagnostic criteria needed to diagnosis or confirm, acute appendicitis!