Stomach (for PBR 2) Flashcards
This is the major cause of chronic gastritis, duodenitis, benign gastric and duodenal ulcers, gastric adenocarcinoma, and MALT lymphoma
Helicobacter pylori infection
Infection is chronic and causes a superficial gastritis, which is most commonly asymptomatic
Approximately 70% of peptic gastric ulcers, 95% of duodenal ulcers, and 50% of gastric adenocarcinoma are caused by this infection
Imaging finding of H. pylori infection
Double-contrast technique demonstrates enlarged areae gastricae in 50% of patients
Diagnosis of H. pylori infection is made by serology, urease breath tests, and endoscopic biopsy
This is third most common GI malignancy, following colon and pancreatic carcinoma
Most (95%) are adenocarcinomas; the remainder is diffuse anaplastic (signet ring) carcinoma, squamous cell carcinoma, or rare cell types
Predisposing factors include smoking, pernicious anemia, atrophic gastritis, and gastrojejunostomy
Gastric carcinoma
H . pylori infection increases the risk of gastric carcinoma sixfold and is the cause of approximately half of gastric adenocarcinoma cases
Gastric carcinoma has four common morphologic growth patterns
What are these patterns?
- Polypoid masses (1/3)
- Ulcerative masses (1/3)
The remaining 1/3
3. Infiltrating tumors
4. Focal plaque-like lesions with central ulcers
5. Diffusely infiltrating
…with poorly differentiated carcinomatous cells producing bizarre thickened folds and thickened rigid stomach wall, so-called scirrhous carcinomas
*Creator’s notes: 4 pattern by 5 were mentioned (?)
This term may be applied to described the resulting stiff narrowed stomach.
“Linitis plastica” and “water bottle stomach”
Hematogeous metastases of gastric carcinoma involves what organs?
Liver
Adrenal glands
Ovaries
Rarely - Bone and lung
Intrapertineal seeding of gastric carcinoma presentas as what?
Carcinomatosis or Krukenberg ovarian tumors
Finding of early gastric cancer on barium study
- Gastric polyps (with risk of malignancy increased for lesions larger than 1 cm)
- Superficial plaque-like lesions or nodular mucosa
- Shallow, irregular ulcers with nodular adjacent mucosa
These lesions are most sensitively detected on double-contrast studies
Findings of gastric carcinoma on CT and MR
These modalities are used to determine the extent of tumor to facilitate preoperative planning
- Focal, often irregular, wall thickening (>1 cm)
- Diffuse wall thickening due to tumor infiltration (linitis plastica) (contrast enhancement is common)
- Intraluminal soft tissue mass
- Bulky mass with ulceration
- Rare, large, exophytic tumor resembling leiomyosarcoma
- Extension of tumor into perigastric fat
- Regional lymphadenopathy
- Metastases in the liver, adrenal, and peritoneal cavity
Mucinous adenocarcinomas frequently contain stippled calcifications
True or false
True
What gastric tumor has this imaging features:
Focal wall thickening (>1 cm)
Diffuse wall thickening (linitis plastica)
Large mass
Ulcerated mass that is predominantly intraluminal
Soft tissue stranding from mass into perigastric fat
Adenopathy, peritoneal implants, distant metastases
Gastric adenocarcinoma
What gastric tumor has this imaging features:
Marked wall thickening (4-5 cm)
Circumferential wall thickening without luminal narrowing
Homogeneous attenuation of tumor
Multiple polyps with ulceration
Extensive adenopathy, especially if below the renal hila
Transpyloric tumor spreads to the duodenum
Gastric lymphoma
What gastric tumor has this imaging features:
Large, heterogeneous exophytic mass (>5 cm)
Extensive ulceration of the mass
Prominent necrosis, hemorrhage, liquefaction
Calcification within the tumor
Malignant GIST
What gastric tumor has this imaging features:
Wall thickening similar to primary carcinoma
Focal intramural mass
Ulcerated mural nodule
Direct invasion of the stomach from adjacent tumor
Metastases to stomach
This findings limit treatment of gastric carcinoma to palliative surgery or chemotherapy
Transmural extension, intraperitoneal spread, or distant metastases
The stomach is the most common site of involvement of primary GI lymphoma
True or false
True
It accounts approximately 50% of cases
What are risk factors for gastric lymphoma?
Chronic infection with H . pylori Epstein–Barr virus Hepatitis B virus, Campylobacter jejuni Celiac disease Atrophic gastritis Inflammatory bowel disease
What is the reason why gastric lymphoma has better prognosis than carcinoma?
Because lymphoma remains confined to the bowel wall for prolonged periods of time
What are the four morphologic patterns of gastric lymphoma?
- Polypoid solitary mass
- Ulcerative mass
- Multiple submucosal nodules
- Diffuse infiltration
UGI findings of gastric lymphoma
- Polypoid lesions
- Irregular ulcers with nodular thickened folds
- Bulky tumors with large cavities
- Multiple submucosal nodules that commonly ulcerate and create a target or “bull’s- eye” appearance
- Diffuse but pliable wall and fold thickening
- Rarely, linitis plastica appearance of diffuse, stiff narrowing
CT is the primary imaging modality used to stage lymphoma
What are helpful CT findings in differentiating gastric lymphoma from carcinoma?
- More marked thickening of the wall (may exceed 3 cm)
- Involvement of additional areas of the GI tract (transpyloric spread of lymphoma to the duodenum in 30%)
- Absence of invasion of the perigastric fat
- Absence of luminal narrowing and obstruction despite extensive involvement
- More widespread and bulkier adenopathy
These are most common mesenchymal tumor to arise from the GI tract
Gastrointestinal stromal tumors (GISTs)
Most, but not all, tumors previously classified as leiomyomas, leiomyosarcomas, and leiomyoblastomas are now classified as GISTs
Approximately 60% to 70% of GISTs arise in the stomach and 10% to 30% of these are malignant
Characteristics of gastrointestinal stroma tumors
Long-term silent growth to a large size
The overlying mucosa is commonly ulcerated
Dystrophic calcification is relatively common in both benign and malignant tumors (helps differentiate these lesions from other gastric tumors)
Predominantly extraluminal
in GIST - difference between benign and malignant
Benign tumors;
Smaller (4 to 5 cm, average size)
Homogeneous in density
Uniform diffuse enhancement
Malignant tumors:
Larger (>10 cm) with central zones of low density caused by hemorrhage and necrosis and show irregular patterns of enhancement
Presentation of metastasis in the stomach
May present as submucosal nodules or ulcerated masses
Most are hematogenous metastases
Rich blood supply results in common involvement of the stomach and small bowel
What are common primary tumors that metastasize to the stomach?
Common primary tumors are melanoma and breast and lung carcinoma
Breast cancer metastases may cause linitis plastica
Kaposi sarcoma involves the GI tract in 50% of patients with what disease?
Patients with disseminated AIDS
Imaging finding of GI Kaposi sarcoma
Double-contrast studies:
Flat masses with or without ulceration, polypoid masses, irregularly thickened folds, multiple submucosal masses, and linitis plastica
CT:
Enhancing adenopathy in the porta hepatis, mesentery, and retroperitoneum
*Creator’s note: Not very specific
These are adenomatous polypoid masses that produce multiple frond-like projections
Villous tumors
Most are solitary and 3 to 9 cm in size although giant tumors may be as large as 15 cm
Malignant potential is high and varies with size of the lesion
(50% for 2- to 4-cm lesions, 80% for lesions >4 cm)
These are lesions that protrude into the lumen as sessile or pedunculated masses
Their appearance on double-contrast UGI series depends on whether they are on the dependent or nondependent surface
Polyps
A polyp on the dependent surface appears as a radiolucent filling defect in the barium pool
A polyp on the nondependent surface is covered with a thin coat of barium
Polyps are commonly multiple
In gastric polyps
The x-ray beam catches its margin in tangent, resulting in a lesion whose margins are etched in white.
What sign is produced by the acute angle of attachment of the polyp to the mucosa
Bowler hat
Sign that consist of two concentric rings and is produced by visualizing a pendiculated polyp end on
Mexican hat sign
What are the different types of gastric polyps?
Hyperplastic polyps
Adenomatous polyps
Hamartous polyps
These account for 80% of gastric polyps
Most are less than 15 mm in diameter
They are not neoplasms, but rather hyperplastic responses to mucosal injury, especially gastritis
Hyperplastic polyps
They may be located anywhere in the stomach, are frequently multiple, have no malignant potential, but are indicative of chronic gastritis
These account for 15% of gastric polyps and are true neoplasms with malignant potential
Adenomatous polyps
Most are solitary, located in the antrum, and are larger than 2 cm in diameter
Characteristic of a polyp what have risk of malignancy
Larger than 1 cm
Lobulated
Pedunculated
Should be biopsied
Polyps that occur in Peutz-Jeghers syndrome
Hamartomatous polyps
Have no malignant potential
This is a common intramural lesion, usually found in the antrum
Lobules of heterotopic pancreatic tissue, up to 5 cm in size, are covered by gastric mucosa
Most are nipple- or cone-shaped with small central orifices
Ectopic pancreas
This refers to an intraluminal gastric mass consisting of accumulated undigested material
Bezoar
Stones may be ingested or form with the bezoar
Any ingested foreign body may produce an intraluminal filling defect
Bezoars may be composed of a wide variety of substances
This bezoar is composed of hair
Trichobezoars
Bezoars may be composed of a wide variety of substances
This bezoar is composed of fruit or vegetable products
Phytobezoars
Bezoars may be composed of a wide variety of substances
This bezoar consist of tablets and semi-solid mass of drugs
Pharmacobezoars
Causes of multiple gastric filling defects
- Hyperplastic polyps
- Adenomatous polyps (especially with polyposis syndromes)
- Metastases
- Lymphoma
- Varices
Key points in thickened gastric folds/ thickened wall
Irregular, focal (< 5m length), asymmetric bowel wall thickening suggest:
a. Benignancy
b. Malignancy
b. Malignancy
Regular, homogeneous, symmetric bowel wall thickening suggests a benign process
Key points in thickened gastric folds/ thickened wall
Diffuse bowel wall thickening (>6 cm in length) is usually caused by:
a. benign process
b. malignant process
A. benign process
Caused by benign inflammatory, ischemic, or infectious diseases
Key points in thickened gastric folds/ thickened wall
Following intravenous contrast administration, bowel wall thickening that shows alternating densities of high and low attenuation (target appearance) is nearly always:
a. benign
b. malignant
a. benign
Nearly always benign and secondary to inflammation or ischemia
The low-density layer is indicative of bowel wall edema
Key points in thickened gastric folds/ thickened wall
Perigastric fat stranding disproportionally more severe than the degree of wall thickening suggests what process?
Inflammatory process
*Creator’s note: does not specify if benign or malignant process
Hallmarks of gastritis
Thickened folds and superficial mucosal ulcerations (erosions)
Thethickened folds are usually caused by mucosal edema and superficial inflammatory infiltrate
These are defined as defects in the mucosa that do not penetrate beyond the muscularis mucosae
Erosions
Erosions heal without scarring
These are also called as varioliform erosions
These are complete erosions that appear as tiny central flecks of barium surrounded by a radiolucent halo of edema
Aphthous ulcers
These may mimic erosions, appearing as distinct punctate barium spots but without the distinctive radiolucent halo of a true erosion
Barium precipitates
Gastritis is commonly accompanied by duodenitis
True or false
True
CT findings of gastritis
- Wall thickening of the distal stomach and duodenum, often with target appearance indicating wall edema
- Involved mucosa may enhance avidly
- Edematous stranding in the perigastric and periduodenal fat
Different types of gastritis
H. pylori gastritis Erosive gastritis Crohn gastritis Atrophic gastritis Phlegmonous gastritis Emphysematous gastritis Eosinophilic gastroenteritis Menetrier disease
This is the most common form of gastritis and is the most common cause of thickened gastric folds
Helicobacter pylori gastritis
Almost all patients with benign gastric and duodenal ulcers have H. pylori gastritis
UGI findings of H. pylori gastritis
- Thickening (<5 mm) of gastric folds
- Nodular folds
- Erosions
- Antral narrowing
5, Inflammatory polyps - Antral narrowing
- Enlarged areae gastricae
This gastritis is most often caused by alcohol, aspirin, and other nonsteroidal anti-inflammatory agents, or steroids
Erosive gastritis
UGI findings of erosive gastritis
- Erosions (aphthous ulcers)
- Thickened, nodular folds in the antrum
- Limited distensibility of the antrum
- Wall stiffness and limited peristalsis
This gastritis characteristically involves the gastric antrum and proximal duodenum
Early-stage disease manifests as aphthous ulcers identical to those seen with erosive gastritis
More advanced disease shows antral narrowing, wall thickening, and fistulas
Crohn gastritis
This gastritis is a chronic autoimmune disease that destroys the fundic mucosa but spares the antral mucosa
Destruction of parietal cells results in decreased acid and intrinsic factor production that lead to vitamin B12 deficiency and pernicious anemia
Atrophic gastritis
UGI findings of atrophic gastritis
- Decreased or absent folds in the fundus and body (“bald fundus”)
- Narrowed, tube-shaped stomach (fundal diameter <8 cm)
- Small (1 to 2 mm) or absent areae gastricae
This is an acute, often fatal, bacterial infection of the stomach
α-Hemolytic streptococci are the most common cause, but a variety of other bacteria have also been identified
It may arise as a complication of septicemia, gastric surgery, or gastric ulcers
Phlegmonous gastritis
Findings of phelgmonous gastritis
Multiple abscesses are formed in the gastric wall, which is markedly thickened
The rugae are swollen
Barium may penetrate into abscess crypts in the gastric wall
Peritonitis develops in 70% of cases
Healing usually results in a severely contracted stomach
This is a form of phlegmonous gastritis caused by gas- producing organisms, usually Escherichia coli, Clostridium welchii, or mixed infections with Staphylococcus aureus
Most cases are caused by caustic ingestion, alcohol abuse, surgery, trauma, or ischemia
Emphysematous gastritis
Multiple gas bubbles are apparent within the wall of the stomach
Gastric folds are thickened and edematous
This is a rare disease characterized by diffuse infiltration of the wall of the stomach and small bowel by eosinophils
Any or all layers of the wall may be involved
Eosinophilic gastroenteritis
The condition is associated with a peripheral eosinophilia as high as 60%
Findings of eosinopholic gastroenteritis
Initially, the folds are markedly thickened and nodular, especially in the antrum
When chronic, the antrum is narrowed with a nodular “cobblestone” mucosal pattern
Ascites and pleural effusions may be present
This is also called as giant hypertrophic gastritis
Condition characterized by excessive mucus production, giant rugal hypertrophy, hypoproteinemia, and hypochlorhydria
Menetrier disease
Pathologically patients have mucosa thickened by hyperplasia of epithelial cells
UGI findings of Menetrier disease
- Markedly enlarged (>10 mm in the fundus) and tortuous but pliable folds in the fundus and body, especially along the greater curvature, with sparing of the antrum
- Hypersecretion that has diluted the barium and impaired mucosal coating
CT finding of Menetrier disease
Demonstrates nodular markedly thickened folds with smooth serosal surface and normal gastric wall thickness between folds
Varices are most common in what area?
Fundus and usually accompany esophageal varices
Isolated gastric varices occur with splenic vein occlusion
MDCT with bolus contrast enhancement is an excellent method for confirming the presence of gastric varices as well as demonstrating their cause
CT findings of varices
CT shows well-defined clusters of rounded and tubular enhancing vessels
Additional findings of portal hypertension may be evident
Most common location for gastric neoplasm
Distal stomach
Lymphoma and superficial spreading gastric carcinoma may produce distorted rigid gastric folds that are commonly ulcerated and appear nodular
Definition of gastric ulcer
Full-thickness defect in the mucosa
About 95% of ulcerating gastric lesions are benign
Diagnostic method of choice for gastric ulcer
Gastroduodenal endoscopy
Signs of ulcers on UGI
- Barium-filled crater on the dependent wall
- A ring shadow caused by barium coating the edge of the crater on the nondependent wall
- A double ring shadow if the base of the ulcer is broader than the neck
- A crescentic or semilunar line when the ulcer is seen on tangent oblique view
Causes of benign gastric ulcers
H. pylori infection
Chronic use of NSAIDs
The effects of the two conditions are additive for development of peptic disease
Alcohol and smoking are other exacerbating factors
Major complications of peptic ulcer disease
Bleeding
Perforation
Obstruction
Most gastric ulcers are:
a. benign
b. malignant
Benign
What is the hallmark of benign ulcers and the basis of radiographic signs of benignancy
Mucosa that is intact to the very edge of an undermining ulcer
Sign of benignancy in gastric ulcer
- Smooth ulcer mound with tapering edges
- An edematous ulcer collar with overhanging mucosal edge
- An ulcer projecting beyond the expected lumen
- Radiating folds extending into the crater
- Depth of ulcer greater than width
- Sharply marginated contour
- Hampton line (a thin, sharp, lucent line that traverses the orifice of the ulcer)
This is caused by an overhanging gastric mucosa in an undermined ulcer
Hampton’s line
Best demonstrated on spot films obtained with compression
CT scan finding of benign gastric ulcer
- Wall thickening usually involving both the antrum and duodenum
- Edema and edematous stranding extending into periantral and periduodenal fat or involving adjacent organs
- Deep ulcers that may show
focal discontinuity of mucosal enhancement and/or outpouching of the lumen
Differential diagnosis for benign ulcers
H . pylori peptic disease Gastritis Hyperparathyroidism Radiotherapy Zollinger–Ellison syndrome
Sign of malignancy in gastric ulcer
- An ulcer within the lumen of the stomach
- An ulcer eccentrically located within the tumor mound
- A shallow ulcer with a width greater than its depth
- Nodular, rolled, irregular, or shouldered edges
- Carmen meniscus sign
This sign describes a large flat-based ulcer with heaped-up edges that fold inward to trap a lens-shaped barium collection that is convex toward the lumen
Carmen meniscus sign
Differential diagnosis of malignant ulcer
- Gastric adenocarcinoma
- Lymphoma
- Leiomyoma
- Leiomyosarcoma
Equivocal ulcers may show the following finding
- Coarse areae gastricae abutting the ulcer
- Nodular ulcer collar
- Mildly irregular folds extending to the ulcer edge
