Pathology of the oesophagus : a) disorders of motility, diverticula, varices b) reflux exophagitis c) esophageal carcinoma Pathology of the stomach : a) gastritis b) peptic ulcer, c) tumors - polyps, carcinoma, lymphoma, stromal tumors. Appendicitis : a) acute - morphologic types, evolution, complications b) chronic - evolution and complications Pathology of the small and large intestine : a) vascular disorders b) inflammatory diseases, infections, enterocolitis c) Crohn´s disease d) ulcerative colitis e) malabsorption syndromes Pathology of the intestines : a) neoplasms b) polyps - non neoplastic, adenomatous - types c) gastrointestinal polyposis syndromes
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Pathology of the oesophagus:a) disorders of motility, diverticula, varicesb) reflux exophagitisc) esophageal carcinoma
Pathology of the stomach:a) gastritisb) peptic ulcer,c) tumors - polyps, carcinoma, lymphoma,
stromal tumors.Appendicitis:
a) acute - morphologic types, evolution, complicationsb) chronic - evolution and complications
Pathology of the small and large intestine:a) vascular disordersb) inflammatory diseases, infections, enterocolitisc) Crohn´s diseased) ulcerative colitise) malabsorption syndromes
Pathology of the intestines:a) neoplasmsb) polyps - non neoplastic, adenomatous - typesc) gastrointestinal polyposis syndromesd) colorectal carcinoma; lymphomase) intestinal lymphomas, stromal tumors
Clinical OverviewEsophagus - most common disorders are reflux esophagitis (due to exposure of the lower esophagus to gastric acid regurgitating upwards from the stomach) and carcinoma, both squamous and adenocarcinoma being important. In children, esophageal atresia and abnormal developmental links with the trachea are important congenital malformations.The stomach is an important site of peptic ulceration, the ulceration being due to breakdown of the normal mechanisms which protect the stomach mucosa from its own acid. The small intestine is the major site of absorption of the basic food materials, and diseases of small intestinal mucosa may lead to malabsorption syndromes; an important cause is celiac disease (gluten enteropathy) which is an immune process leading to destruction of the small intestinal mucosa. The small intestine, particularly ileum, is the most common site for the chronic inflammatory disease called Crohn’s disease. Acute inflammatory disorders of the small bowel are common but transient, being due to bacterial or viral infection. The stomach and colon are usually also involved (infective gastroenteritis).
Most common inflammatory disease of the entire alimentary tract which requires surgical treatment is acute appendicitis, mainly in children and young adults, but occasionally in mature adults and the elderly where the diagnosis may be missed.
The colon may also be involved in the chronic inflammatory condition Crohn’s disease, but is the main site of the chronic intermittent inflammatory disease called ulcerative colitis.
Predisposing factors to colonic cancer - neoplastic polyps in the colonic mucosa (adenomatous polyps).
Colorectal carcinoma there is a well-recognized sequence ofchanges from benign polyp to invasive adenocarcinoma. Colon - mechanical abnormalities diverticular disease and volvulus. Disorders of the anus are a frequent are mainly trivial with distressing symptoms (hemorrhoids, pruritus ani, anal fissure); the only life-threatening disease of the anus is squamous carcinoma.
GIT is susceptible to bacterial and viral infection, producing acute vomiting and diarrhea, the main source for the infection being contaminated or infected food items (‘food poisoning’).
Vascular diseases affecting the alimentary tract are uncommon, with the exception of arterial infarction of the small bowel due to thrombotic or embolic occlusion of the mesenteric vessel, and acute venous infarction of small or large bowel due to some mechanical obstruction to normal venous drainage.
The most common examples of venous infarction of the bowel are strangulation of a loop of small bowel in a hernial sac and volvulus of the large bowel.
Esophagus
Lesions – esophagitis to cancerDysphagia (difficulty in swallowing) esophageal motor dysfunction,Narrowing, or obstructionClinical manifestations1.Heartburn (retrosternal burning pain) –
regurgitation of gastric contents2.Hematemesis3.Melena
Esophagus
Anatomic disorders of the esophagus1.Stenosis- lower esophageal narrowing,
chronic inflammation, GERD2.Atresia, fistula- newborn with
3.Webs, rings- dysphagia to solid foods, partially occluding lumen
4.Diverticula- nocturnal episodic regurgitation
Hiatal hernia- dilated segment of the stomach to protrude above the diaphragm
Sliding- 95% of cases, 9% with heartburn (accentuated by bending forward, supine position, obesity)
Paraeophageal- separate portion of the stomach enters the thorax through
a widened foramen, rarely with reflux, can become strangulated/ obstructed
Complications- ulceration, bleeding, perforation
EsophagusAchalasia- incomplete relaxation of the lower
esophageal sphincter to relax during swallowing:1.Aperistalsis2. Incomplete relaxation3. Increased resting tonePrimary- loss of intrinsic inhibitory innervation of the
lower esophageal sphincter and smooth muscle segment
Secondary- Chagas disease (Trypanosoma cruzi) -myenteric plexus of the GIT
Other possible causes- autoimmunity, previous viral infection (unproven)
EsophagusBarrett esophagus- complication of a long-
standing GERDUp to 10% of patients with persistent symptomatic
reflux disease-replacement of the distal stratified squamous
mucosa by metaplastic columnar epithelium containing goblet cells (more resistant to gastric content)
male: female ratio = 4:1, common among whitesComplications1.Ulcer, stricture2.Cancer – 30 to 40-fold increase
EsophagusEsophageal CASquamous CA- 90% of cases, > age 50, male:female ratio 3:1Adenocarcinoma- increasing incidence, more among whitesMorphologyEarly – small gray-white thickening or elevation of the mucosa3 types1. exophytic, protrude into lumen2. Necrotizing, erodes into the respiratory tree, aorta, elsewhere3. Diffuse infiltrativeInvolvement
Cervical- 20%Middle third – 50%Lower third – 30%
EsophagusEsophageal CAAdenoca-arise from dysplastic mucosa of Barrett esophagusUsually in the distal third Micros- mucin-producing glandular tumorCMInsidous onset, dysphagia and obstruction -weight loss, anorexia, fatigue, weakness-pain related to swallowingSurgical excision is rarely curative – lymphatic
network, adjacent structureAmenable to surgery if confined to mucosa or submucosa
Chronic gastritis-chronic mucosal inflammatory changes lead to mucosal atrophy and epithelial metaplasia-Helicobacter pylori- non-invasive non-spore forming gram negative rod, bacterial enzymes and toxins, release of chemicals by recruited neutrophil-autoimmune gastritis- gland destruction and mucosal atrophy,loss of parietal cellsMorphology- chronic gastritis- inflammatory changes consist of lymphocytic and plasma cell infiltrate in the lamina propria with variable gland loss and mucosal atrophyCM- few or no symptoms, upper abdominal discomfort, n/vMost patients with peptic ulcer have H. pylori infections, risk for gastric CA 5XAutoimmune gastritis, risk for cancer from 2% to 4%
Stomach
Acute gastritis-acute mucosal inflammatory process, usually of transient nature, may be accompanied by bleeding and mucosal erosionPathogenesis-NSAID(aspirin)Excessive alcohol intake, heavy smokingAnti-cancer drugsUremiaSystemic infection (typhoid fever)Severe stress (trauma, burns, surgery)Ischemia and shockSuicide using acid or alkaliMechanical trauma (NGT)
Stomach
Acute gastritisMorphology- localized to diffused involvement, superficial inflammation of the entire mucosa thickness, with bleeding and erosion (acute erosive gastritis)If the noxious event is short lived – complete recovery of the mucosaCM- asymptomatic, epigastric pain with N/V, hematemesis, melena, possible fatal blood loss-major cause of hematemesis (alcoholics)-25% of patients taking aspirin for RA develop acute gastritisGastric ulcerationBreach in the mucosa, could extend to muscularis mucosae into submucosa or deeper
Stomach
Peptic ulcers-chronic, often solitary, due to aggressive action of
acid-peptic juices98% in the first portion of duodenum or stomach
(ratio 4:1)American- 2.5% males, 1.5% femalesGenetic or racial factors- plays no role in its causationDuodenal ulcers- alcoholic cirrhosis, COPD, chronic
(multiple peptic ulcers - gastrin secretion by a tumor)
Stomach
Peptic ulcerMorphologyMucosal defects that penetrates deeper, mostly round, sharply punched out craters 2 to 4 cm.Sites- ant and post wall duodenum, lesser curvatureNo significant elevation or beading of the edges
Micros- vary with activity, chronicity, degree of healingDiff from AGU- absent gastritis in adjacent mucosaCM- epigastric gnawing, burning, boring pain, worse at night, occurs 1 to 3 hours after mealsRelieve by alkali or food (there are many exceptions)Other- n/v, bloating, belching, weight lossBleeding- chief complication, perforation, malignant transformation
PU- chronic and recurrent, impairs quality of life than shorten it Requires 15 years for healing
Morphology – circular and small (less than 1 cm), base dark brown, singly to multiple throughout stomach and duodenum
CM- ICU admitted patients with sepsis, burns or trauma dev AGUTreatment- prophylactic antacid, blood transfusionNeed to correct the underlying conditionGastric mucosa can recover completely if the patient does not die.
Stomach
TUMORSGastric polyps- mass or nodule that project
above the level of the surrounding mucosa, these are uncommon
Types1.Hyperplastic – 80% to 85%2.Fundic gland – 10%3.Adenomatous – 5%
All arise from a setting of chronic gastritis – adematous polyp has a risk of containing an adenoCA
plexuses.Functional obstruction, distension of the colon
proximal to the affected segmentCM- delay in the initial passage of meconium,
followed by vomiting 48 to 7 hoursEnterocolitis, fluid and electrolyte imbalance, perforationAcquired megacolon• Chaga’s disease –trypanosomes• Obstruction by neoplasm, inflammatory stricture• Toxic megacolon complicating CD or UC
Small and Large Intestines
VASCULAR DISORDER
Ischemic bowel diseaseIntensive infarction – occlusion of any of the major arteries- celiac, superior and inferior mesenteric arteriesTransmural – acute occlusion of the major mesenteric
arteryMural or mucosal – physiologic hypoperfusion, localized
CM- most common in the later years of life, transmural sudden onset of abdominal pain, sometimes with bloody diarrhea, need for prompt diagnosis(recent major abdominal surgery, recent MI, atrial fib) mortality rate = 90%
Diarrheal diseases-increase stool mass, stool frequency, stool fluidity, often with pain, urgency, perianal discomfort, incontinence
Dysentery- low volume, painful, bloody diarrhea
MalabsorptionGluten-sensitive enteropathy- Celiac disease- reduced small intestinal absorptiveSurface area- sensitivity to gluten (oat, barley, rye) immune response- damage to surface enterocyte-symptomatic diarrhea and malnutrition from infancy to mid-adulthood,Removal of gluten in diet results in dramatic improvementTropical sprue, whipple disease- arise from intestinal infectionresults in celiac-like disease within few days after acute diarrheal enteric infection-rare, affects intestine, CNS, joint. Hallmark PAS-positive macrophages in the lamina propria. Etio-gram + and culture R actinomycete (tropheryma whippelli) males, 4th to 5th decades of life- -malabsorption, lymphadenopathy, hyperpigmentation, polyarthritis, obscure CNS complaintsCM- bulky frothy, greasy, yellow or gray stool with weight loss, anorexia, Abdominal distention, borborygmi, flatus, muscle wasting
Consequences of malabsorption
IDIOPATHIC INFLAMMATORY BOWEL DISEASE
Crohn disease, ulcerative colitisChronic relapsing disorders of unknown originCollectively called IBD. Normal intestine represents adynamic balance between1. Factors that activate the host immune system –such as
2. Host defenses that down regulate inflammatory and maintain integrity of the mucosa
IBD is a heterorogenous group of diseases characterized by exaggerated destructive mucosal immune response.
Tissue injury is likely to be initiated by diverse genetic and immunologic
pathways that are modified by environmental influences, including microbes and their products
CROHN DISEASEInvolves any level of the GIT, associated with complication
of immune origin like iritis, uveitis, migratory polyarthritis, it is a systemic inflammatory disease with predominant GIT involvement, peaks 2nd to 3rd decade of life, more among women, whites, Jews
Characterized by transmural involvement with mucosal damage, caseating granuloma 40% to 60% cases, fissuring and fistulae, sinus tract formation. Thick and rubbery wall. “string sign”. Skip lesion. Microscopic- inflammation, crypt abscess, ulceration, chronic mucosal damage.
CM- variable presentation, recurrent diarrhea, crampy abdominal pain, fever lasting days to weeks, melena- 50%, 10-20% symptom free for decades after initial attacks, 20% continuous active disease
Complications- fistula, abdominal abscess, strictures/ obstructionRare- massive intestinal bleeding, toxic dilatation of colon, cancer
ULCERATIVE COLITISulceroinflammatory disease – colon, limited to the mucosa
and submucosa except in severe cases, begins in rectum
Epidemiology- more common than CD, whites, no sex predilection, peaks at age 20 to 25
Morphology- involves rectum or rectosigmoid colon only in 50% of cases, pseudopolyps- isolated islands of regenerating mucosa
CM- relapsing and remitting disorder- bloody mucoid diarrhea persists for days, weeks, months. Insidious, cramp, tenesmus, colicky abdominal pain relieved by defecation. Fever, weight loss. 10% first attack is the last
ULCERATIVE COLITIS
Colonic diverticulosisDiverticulum- uncommonBlind pouch leaving off the gut, lined by a mucosa. Most diverticulitis are acquired, lacking or having attenuated muscularis propria.Common site for diverculum- colon,
diverticular disease of the colon -diverticulosisCommon among western adults, prevalence is about 50% by age 60-low fiber diet, reduced stool bulk, exaggerated spastic contraction- herniation of the bowel wallPathogenesis1.Exaggerated peristaltic contractions- increase intraluminal pressure2.Focal defect in the muscular colonic wall
Bowel obstruction80% of cases due to; hernias, intestinal adhesions, intussusception, volvulus (small intestines commonly involve due to its small lumen)Hernial sac- protrusion of a pouch-like sac through a weakness or defects in the abdominal cavityUsual sites anteriorly1.Inguinal and femoral canals2.Umbilicus3.Surgical scar
Incarceration- permanently trappedStrangulation- infarction due to compromised blood supplyAdhesions-surgery, infection, endometriosis- intestine are trapped (internal hernia)Intussusception- telescoping of proximal segment into a immediately distal segment - Common in children may be due to excessive peristaltic activity. Adults- Intraluminal mass (tumor)- infarction
Volvulus- twisting of bowel loops about its base of attachment- small intestines
TumorsEpithelial tumors of the intestines are major causes of diseases and death worldwide
Colorectal cancer second only to bronchogenic carcinoma among the cancer killersAbout 5% Americans will develop colorectal cancer, 40% of them will die of the disease
Adenocarcinoma most common colorectal canceraccounts for 70% of all GIT malignancy.
Small intestine uncommon site for tumor, Polyp- mass protrudes into the lumen- 1. pedunculated, (stalk) 2. sessile-formed by abnormal mucosal maturation, inflammation, architecture No malignancy potential (hyperplastic polyp)-those that arise due to epithelial proliferation and dysplasia (adenomatous polyp or adenoma)Precursor of cancer
Tumors of the large intestinesAdenomasSmall to large lesions, mostly sessilePrevalence – 20% to 30% before age 40,
40% to 50% after age 60Most invasive colorectal adenoCA arise from preexisting adenomatous lesionTypes- tubular, villous, tubulovillous
Malignant risk- polyp size, histologic architecture, severity of dysplasia
-Ca is rare in tubular adenoma < 1 cm-Ca is high (40%) in sessile villous adenoma > 4 cm-Severe dysplasia often found in villous areas(maximum diameter chief determinant for having cancer)CM- small ones- asymptomatic, occult bleeding can lead to anemia, occult bleeding – villous adenomaAll adenoma are potentially malignant
Colorectal CA98% of all cancer in large intestines –
adenocarcinoma arise from adenomatous polyps134,000 new cases/ year, 55,000 deaths, 15% of all cancer-related deaths USAEpidemiologyPeak age 60-70, less than 50% seen in less than 50 y/o if seen consider; ulcerative colitis, polyposis syndromeAdenoma are presumed precursor lesionsMales affected 20% more often than femalesHighest incidence rates in developed countriesEnvironmental factors- dietary practice1.Low content of unabsorbable vegetable fiber2.High content of refined carbohydrates3.High fat content4.Decrease intake vitamin A C E – increased fecal retention, altered bacterial flora
Colorectal CAAdenoma-carcinoma sequence- documented by these observation1. Population with high prevalence of adenomas high prevalence of
colorectal ca2. When invasive a is identified at an early stage surrounding
adenomatous tissue is also presentMorphology25%- colorectal ca – cecum or ascending colon25%- descending colon and proximal sigmoid
Tumors at Proximal colon- exophytic mass, obstruction is uncommon Distal colon- annular encircling lesion – napkin ring constriction
Microscopic- adenoCA well-differentiated to undifferentiated
CM-asymptomatic and develops insidiouslyR-sided- fatigue, weakness, iron deficiency anemiaL-sided- occult bleeding, change in bowel habit, crampy left lower
quadrant discomfortMetastasis- regional LN, liver, lungs, bonesSurgically curative in 25% to 30% of casesMost important prognostic indicator of CRC is the stage of the disease
Small intestinal neoplasmsComprises 75% of the length of the GIT, tumor – 3% to 6% of the GITadenoCA- common site- duodenumCM- late, cramping pain, N/V, weight lossCarcinoid tumor- carcinoma-like, tendency for aggressive
behavior1. Site of origin2. Depth of penetration3. Size of tumor90% of ileal, colonic and gastric carcinoid have metastases during
time of diagnosiscan secrete bioactive products or hormones
Morphology – appendix most common site, bulbous swelling of the tip, obliterate the lumen
Solid, yellow-tan appearance, firm due to desmoplasiaRectal and appendiceal carcinoids almost never metastasizeMicroscopic- form discrete islands, trabeculae, strands, glands or
undiffentiated sheetMonotonous appearance with scanty pinkish cytoplasm, round to
oval stippled nuclei minimal variation in cell or nuclei size
Small intestinal neoplasmsCarcinoid syndrome- clinical features