Pathoma Gastrointestinal Pathology Flashcards
What is the triad of Behcet syndrome?
- Recurrent aphthous ulcers
- Genital ulcers
- Uveitis causing visual disturbances
- > etiology is unknown
What are the risk factors for squamous cell carcinoma in the oral cavity? Where does it most often arise?
Tobacco smoking and alcohol
Chewing betel nut (Asian cultures it’s like chewing tobacco)
Most often arises in the floor of the mouth
What does erythroplakia look like and is it more or less worrying than leukoplakia?
Smooth, soft, flat, or slightly eroded red patch which is not otherwise accounted for (looks like a pizza burn)
More worrying -> often highly dysplastic or representing squamous cell carcinoma with subjacent inflammation
What is sialadenitis and what typically causes it?
Acute or chronic inflammation of the salivary gland:
Acute:
Bacteria - i.e. Staph aureus, can cause or complicate it by filling it with pus -> generally preceded by sialolithiasis.
Chronic:
Parotid glands - often viral infection like mumps or HIV
Autoimmune disorders like Sjogren’s syndrome may cause it
What are the clinical features of pleomorphic adenoma and what is its most common problem?
Painless, slowing-growing mass usually in parotid gland
Treatment is possible with complete surgical excision, but margins are so irregular that the surgeon can miss some and it will come back
Mass is nodular and appears generally well circumscribed, but the surgeon must take a generous margin
What is the uncommon complication of pleomorphic adenoma? How does this present?
Carcinoma can arise within it, and it is an aggressive malignancy
Will present with signs of a facial nerve palsy if in parotid gland, as it is neurotropic (similar to how pancreatic adenocarcinoma is)
How does pleomorphic adenoma appear microscopically?
Heterogenous (pleomorphic) mixture of epithelial and mesenchymal tissues with no atypia (benign).
Epithelial component - tubules, glands, cords, or nests
Stromal areas - myxoid, fibrous, CARTILAGINOUS, or even osseous
What is a Warthin tumor and who gets it? Is it malignant?
Papillary Cystadenoma Lymphomatosum
Always arises in the parotid gland in male smokers
Malignant in 10%, bilateral in 10% (like pheochromocytoma)
How does Warthin tumor appear microscopically?
Microscopically - Cystic spaces with tall pink columnar epithelial cells with abundant eosinophilic cytoplasm (arise from striated ducts). They produce chemoattractants so there will be a dense lymphoid stroma underneath which looks like germinal centers
(lymph-node-like stroma)
What is the most common malignant primary salivary gland neoplasm and what cell types are associated? Where does it arise?
Mucoepidermoid carcinoma
-> Associated with dysplastic squamous and mucinous cells
Arises in the parotid gland. Because it’s malignant, it can cause facial nerve problems.
What is the characteristic pregnancy finding for a tracheo-esophageal fistula and what is the most common type?
Characteristic finding - polyhydramnios (can’t swallow)
Most common type: Esophageal atresia with distal tracheo-esophageal fistula
What are esophageal webs?
Protrusion of esophageal mucosa (only the outer layer), most commonly in the upper esophagus
Where does Zenker diverticulum occur? What type of diverticulum is it?
Killian's triangle Between thyropharyngeus (superiorly) and cricopharyngeus (inferiorly), both of which are components of the inferior constrictor muscle
It is a FALSE diverticulum (just propulsion of the mucosa)
What are the two esophageal syndromes associated with violent wretching and which is more serious? why?
- Mallory-Weiss syndrome - partial-thickness longitudinal mucosal lacerations at GE junction
- Boerhaave syndrome - transmural, distal rupture due to violent wretching -> can cause mediastinitis and subcutaneous emphysema (due to air in mediastinum) and is a surgical emergency
What is the most common cause of death in cirrhosis? How can you differentiate it from Mallory-Weiss syndrome?
Ruptured esophageal varices with associated coagulopathy due to liver dysfunction
Presents with painLESS hematemesis (vs Mallory-Weiss which is painful)
Where is the venous drainage from from the upper 1/3, middle 1/3, and lower 1/3 of the esophagus? Where does the portal system connect?
Upper 1/3 - Superior vena cava via inferior thyroid veins
Middle 1/3 - azygous system
Lower 1/3 - portal system via left gastric vein (coronary vein (supplies the cardia of the stomach)), which forms an anastamosis with the azygous system
What are the two plexuses found in the wall of the GI tract? Where are they located and what is their function?
Meissner’s - subMucosal - receive sensory input from esophageal wall layers
Auerbach’s - Arnold S. = Muscles - Myenteric - sits between IC and OL layers of muscularis propria (externa) -> coordinates peristalsis
What is happening pathophysiologically to cause achalasia?
Loss of Auerbach’s (myenteric) plexus, with preferential loss of inhibitor neurotransmitters like NO and VIP -> tonically increased sphincter contraction
What can cause achalasia?
Primary - neurological degeneration
Secondary - Chagas’ disease, viral infection, autoimmune diseases
What are the risk factors for GERD / Reflux Esophagitis?
Same as sliding hiatal hernias
-> things that decrease sphincter tone or increase intraabdominal pressure
i.e. hiatal hernia, obesity/pregnancy, delayed gastric emptying (increased pressure and acidic stomach pH)
only thing not explained: alcohol and tobacco use -> they are irritants
What are the two types of diaphragmatic hernias and which is most common?
- Sliding hiatal hernia - GE junction slides into mediastinum, giving hourglass appearance - most common. Sometimes associated with a Schatzki B ring.
- Paraesophageal / rolling hiatal hernia - fundus of stomach prolapses into thorax adjacent to GE junction
What are the classic findings and potential complications of paraesophageal hernia?
- Bowel sounds in the lower lung field (fundus of the stomach is herniated in the mediastinum next to the esophagus)
- Lung hypoplasia - last room for lung to expand.
- Strangulation and perforation of involved fundic stomach (compromising blood flow)
How is GERD associated with asthma?
Reflux of acid down the esophagus can irritate the airway
-> causing coughing and adult-onset asthma.
What are the complications of GERD?
- Stricture formation
- Barrett esophagus -> NONCILIATED columnar epithelium with goblet cells
- Erosion / ulceration of esophagus with possible bleed (Rare)
What type of esophageal carcinoma is most common in the US and where does it arise?
Adenocarcinoma - progression from Barrett esophagus
-> has all the same risk factors as those for GERD
Arises in the lower 1/3 of the esophagus, especially the GE junction.
What type of esophageal carcinoma is most common in the rest of the world and what are its risk factors? Where does it arise?
Squamous cell carcinoma, arises usually mid-esophagus but can be anywhere
RF: alcohol and tobacco smoking**, hot liquids and achalasia (irritation), caustic strictures with repeated injuries, Plummer-Vinson, etc
Where does the upper 1/3, middle 1/3, and lower 1/3 of the esophagus drain its lymph? Note that this is the pattern of spread of esophageal carcinoma.
Upper 1/3 - Deep cervical nodes
Middle 1/3 - Mediastinal nodes
Lower 1/3 - Gastric and celiac nodes
Think neck, lung, stomach
Why does squamous cell carcinoma spread easily?
Because it lacks an outer serosal layer, it locally extends to other mediastinal organs, even aorta causing a massive bleed
Can also infiltrate lymphatics and spread hematogenously
How does omphalocele occur and is its prognosis better or worse than gastroschisis?
Ompalocele - failure of physiologic hernation (which occurs during growth rotation of gut during development) to return from umbilical cord back into abdomen. Will be covered by peritoneum and amnion “cele”‘d.
Prognosis is worse than gastroschisis even though it looks less ugly, because more genetic abnormalities are associated with it
What is gastroschisis? Where does it typically happen?
Extrusion of abdominal contents through abdominal wall, not covered by peritoneum or amnion -> typically due to an abdominal wall defect on the right side
Can be repaired surgically
What type of diverticulum is a Meckel diverticulum and what causes it?
A true diverticulum - all layers of the abdominal wall
Caused by a failure of the regression of the vitelline duct, which normally communicates with the yolk sac during development -> “vital” for nutrients to the midgut
2 inches long, 2 feet from ileocecal valve, in 2% of the population, occurring in first two years of life
Who tends to get hypertrophic pyloric stenosis, and what are the common presenting signs and symptoms?
Firstborn Caucasian males
- Olive-shaped mass in epigastric region
- Visible peristaltic waves after eating (hypertrophy)
- Nonbilious projecting vomiting starting after feedings about 3-4 weeks after birth (takes a while for food to build in stomach)
What things cause decreased mucosal protection to cause acute gastritis?
- Advanced age - decreased mucus production
- NSAIDS, corticosteroids - loss of PGE2, which is needed to maintain blood flow to mucosa / sweep away acid, and maintain production of HCO3- / mucin
- Uremia - acidosis will allow less bicarbonate to be excreted
- Low O2 -> shock, high altitudes, severe burns -> mucosal ischemia = poor protection
What things tend to induce acute gastric ulcers?
- NSAIDs
- Intracranial trauma - stimulation of vagal nerve increases gastric acid secretion
- Major physiologic stress - shock, sepsis, burns leads to decreased perfusion of mucosa (decrease nutrients) and systemic acidosis (Decrease bicarbonate excretion)
What is it called when you have an ulcer due to intracranial injury vs significant burns?
Intracranial injury = vagal stimulation -> Cushing ulcer (think of Cushing’s triad)
Burns = hypovolemia -> Curling ulcer (think of Curling irons are hot) -> decreased mucosal perfusion
What is the most common cause of chronic gastritis? Where does it start and how do you get it?
H. pylori - 90% of cases
Typically starts in the antrum of the stomach
More a disease of lower SES in the US, thought to spread via oral-oral or fecal-oral
How can the inflammation in autoimmune gastritis be told apart from H. pylori gastritis?
Autoimmune - chronic inflammatory infiltrate will be deep within the mucosa near the parietal and chief cells, and will also be in the body / fundus rather than antrum
Other than H. pylori, what are some other causes of Peptic ulcer disease (the more chronic form of acute gastritis)?
NSAIDs - especially gastric peptic ulcer disease (i.e. chronic treatment of RA)
Corticosteroid use and psychological stress - inhibit repair by immune system + mucosal protection (blocks PLA2)
Hypercalcemia -> increases gastrin (abdominal pain in hypercalcemia)
Zollinger-Ellison syndrome -> Gastrinoma
What causes Menetrier disease and how does it appear?
Increased production of TGF-alpha leads to diffuse hyperplasia of mucous glandular epithelium (foveolar) in body and fundus, with atrophy of parietal and chief cells -> thick rugae
What are the complications of Menetrier disease?
Protein-losing enteropathy -> increased mucin secretion leads to diarrhea, weight loss, and hypoproteinemia which can lead to peripheral edema
Increased risk for adenocarcinoma (premalignant)
How does H.pylori-induced gastritis (chronic gastritis) appear grossly and microscopically?
Grossly - Erythematous, rough-appearing gastric mucosa with active inflammation. Mucosal atrophy and intestinal G-cell metaplasia and hyperplasia is also present.
Microscopically - acute on chronic inflammation (neutrophils + chronic inflammatory infiltrate) + presence of spiral-shaped bacteria in superficial mucus
How does alcohol cause acute gastritis?
Directly damages the mucosa, decreasing mucosal protection.
What is the difference between an erosion and an ulcer? How does this relate to the three stages of acute gastritis?
- Superficial inflammation - neutrophils and edema.
- Erosion - loss of mucosa of the stomach, not into the submucosa (last layer of mucosa is muscularis mucosa)
- Ulcer - Penetration into the submucosa or deeper
What causes autoimmune gastritis and what part of the stomach does it affect?
Loss of self-tolerance of CD4+ T cells to gastric parietal cells
- > stimulation of autoantibodies to parietal cells or intrinsic factor. Note that these antibodies are markers but do NOT drive the disease
- > chronic inflammation and destruction of gastric body and fundus by CD8 activation
What cancer does chronic gastritis predispose to and why?
Gastric adenocarcinoma
-> chronic inflammation will induce an intestinal metaplasia (similar to Barrett esophagus) -> increases risk of dysplasia / cancer.
What two tests are considered the most reliable for the diagnosis of H. pylori?
- Urea breath test, with C13 or C14
2. Stool test - good sensitivity / specificity for picking up H. pylori antigen, and non-invasive
What cells will hypertrophy in duodenal ulcer? And what is the other cause other than H. pylori?
Brunner’s glands -> to protect the duodenum from acid
Other cause -> ZE syndrome
What are the signs and symptoms of gastric cancer?
Weight loss, pain, NVD, hematemesis, melena
EARLY SATIETY - especially in diffuse type
What is gastric adenoma? When does it typically arise? Where?
A premalignant gastric polyp typically arising in the gastric antrum in chronic atrophic gastritis
- > epithelial dysplasia which will progress to adenocarcinoma
- > picked up in Japan where they actually screen for it
-> fundic gland polyps are the ones associated with PPI use, and then hyperplastic polyps with chronic inflammation + repair
What are the two types of gastric adenocarcinoma and the risk factors for each?
Intestinal-type - Chronic atrophic gastritis of both types (causes intestinal metaplasia), dietary nitrosamines, gastric adenoma, smoking, and blood type “A” (just remember CA).
Diffuse-type - risk factors unknown (thus increasing in prevalence)
Where does intestinal-type gastric adenocarcinoma occur? What does it look like grossly?
In the antrum / pyloric region, where intestinal metaplasia is occuring
Appears as heaped up, ulcerating, necrotic or exophytic mass
What is Diffuse-Type Gastric Adenocarcinoma also called? What mutation is associated with it? What does it look like microscopically?
Signet-Ring Cell Adenocarcinoma
Associated with loss of E-cadherin (similar to invasive lobular carcinoma of breast with single file cells)
Microscopically - mucin-filled cells with peripheral nuclei, widespread over stomach. Infiltrating singly or in small nests (glandular differentiation with intracellular mucin)
What are some more uncommon presenting symptoms for gastric cancer?
Acanthosis nigricans - axillary browning (normally associated with increased insulin resistance)
Leser-Trelat sign - multiple seborrheic keratoses appearing all over body
How does signet-ring cell adenocarcinoma appear grossly?
Linitis plastica - “leather bottle” - stomach wall is grossly thickened and leathery due to diffuse invasion by cells with prominent DESMOPLASIA
What lymph node is commonly enlarged in gastric CA?
What are some very specific sites of metastasis for intestinal and diffuse type gastric adenocarcinoma?
Virchow - left supraclavicular)
Intestinal type - Sister Mary Joseph nodule -> periumbilical nodular metastasis
Diffuse type - Bilateral Krukenberg tumor -> mucinous adenocarcinoma metastases in the ovaries.
What is the most common place for intestinal atresia to occur and what is thought to cause it? What explains the sign seen on X-ray?
Duodenum - failure to recanalize due to loss of blood supply during development
Associated with Down syndrome
Double bubble sign: dilated stomach and proximal duodenum, with intervening constriction via the pyloric sphincter.
What happens in normal rotation of the gut and what will happen if this is done incorrectly?
Normally, the gut rotates 270 degrees around the superior mesenteric artery via a counterclockwise rotation from the frontal view. This allows the colon which was pointing downwards to sit on your right side on your posterior abdomen, anterior to the duodenum
If this is done incorrectly -> malrotation occurs
In what condition are Ladd bands observed and what problems may they cause?
Malrotation of the midgut, with cecum ending up the RUQ rather than RLQ as it should
- > Ladd bands are adhesions formed from peritoneal tissue which connect to the cecum
- > due to mispositioning, these adhesions (which should normally hold the cecum as an intraperoniteal structure) will encircle the duodenum and can cause obstruction of the 2nd part of the duodenum
- > may also cause volvulus of cecum due to narrowed mesentery
TL;DR: duodenal obstruction (presents like duodenal atresia) or midgut volvulus.
Why do Meckel’s diverticula sometimes cause problems?
- Often contains heterotopic gastric mucosa which secretes acid, causing bleeding
- Volvulus (wrap around the diverticulum which is attached to umbilicus), intussusception, or obstruction can occur
- Can present as a fistula which drains into umbilicus
What is it called when a portion of bowel twists on its mesentery and where does it happen in adults? Children
Volvulus -> happens in sigmoid colon in adults due to long mesentery
(coffee bean sign on X-ray)
Children -> happens in cecum, due to association with congenital malformations (i.e. Meckel’s, malrotation)
When does intussusception occur in adults and children?
Adults - associated with intraluminal mass or tumor acting as a lead point
Children - more common -> due to lymphoid hyperplasia (i.e. rotavirus), with terminal ileum telescoping into cecum
What causes the majority of the injury in ischemic bowel disease, and what area is particularly susceptible? What part of the wall is most susceptible to infarct?
Secondary reperfusion injury -> due to oxygen-derived free radicals
Splenic flexure is most vulnerable - watershed area between SMA / IMA
Mucosa is most susceptible to infarct since it is farthest from the blood supply (can be infarcted alone inhypotension)
What is the clinical presentation of ischemic bowel disease / acute mesenteric ischemia?
Abdominal pain (especially postprandial) with some bloody diarrhea - “currant jelly stools”, due to hemorrhagic infarct
- > often seen in post-MI or post-shock patients who have hemorrhagic necrosis
- > often suspected as a diagnosis of exclusion in older adults, when pain is out of proportion for physical exam findings
What is Chronic mesenteric ischemia also known as? How will it present?
“Intestinal angina” - atherosclerosis of celiac artery, SMA, or IMA causes hypoperfusion
- > postprandial epigastric pain due to increased nutrient requirement for digestion
- > food aversion and weight loss in an elderly person
What are classical causes of thrombosis / embolism of the SMA?
Atrial fibrillation, polyarteritis nodosa
What are the classical causes of venous thrombosis of the mesenteric vein?
Hypercoagulable states:
Polycythemia vera
Lupus anticoagulant
What will skin biopsy of Dermatitis Herpetiformis show via H&E and direct immunofluorescence? What forms at the tips of these papillae?
H&E - neutrophilic infiltrate of papillary dermal tips
DIF - granular IgA deposition
- > deposit at papillary tips since this is the farthest they can migrate via blood supply in dermis
- > herptiform vesicles and blisters form at the dermal tips where IgA is being deposited
What is the pathogenesis of Celiac disease?
Gliadin is a soluble portion of grains, is absorbed into GI tract and deaminated by tissue transglutaminase (tTG)
Deaminated gliadin is presented by MHC class II and activates CD4 T cells -> T cell mediated damage of intestinal mucosa
What is seen on anatomic pathology of Celiac disease? Where is the damage worst?
Villous atrophy / blunting with crypt hyperplasia for regeneration, and chronic inflammation surrounding
Worst in proximal small intestine (DUODENUM)
What antibodies are detected by serology in Celiac disease? What antibody types should you look for?
IgA antibodies:
- Anti-tissue transglutaminase (TTG3)
- Anti-deaminated gliadin
- Anti-endomysial antibodies (anti-TTG2) - connective tissue which ensheaths muscle fibers, thought to be cross-reactive to a tissue transglutaminase
Should also check for IgG antibodies since Celiac’s disease is associated with IgA deficiency
What malignancies is Celiac disease associated with?
T-cell lymphoma - due to lymph hyperplasia / inflammation (enteropathy-associated T-cell lymphoma)
Small intestinal adenocarcinoma (rare, associated with the crypt hyperplasia)