1
Q
Thickened gastric folds are most commonly due to what? What type of characteristic fold thickening does this produce?
Nodular fold thickening is suggestive of what? Examples?
A
- Thickened gastric folds are most commonly due to inflammatory gastritis, which characteristically produces smooth fold thickening.
- Nodular fold thickening is suggestive of neoplasm, such as gastric lymphoma or submucosal carcinoma.
2
Q
Causes of Thickened Gastric Folds
What are they?
Provide a brief discussion of each cause!
A
- Helicobacter pylori is a major cause of gastritis, gastric ulcers and duodenal ulcers.
- Zollinger-Ellison is gastrin over-production from a gastrinoma, which is a pancreatic islet cell tumor that has a 50% rate of malignancy.
- ZE features elevated gastrin level and a paradoxical increase in gastrin after secretin administration.
- 25% of patients with gastrinoma have multiple endocrine neoplasia MEN1.
- MEN-1 consists of parathyroid adenoma, pituitary adenoma, and pancreatic islet cell tumors.
- Eosinophilic gastritis is characterized by thickened folds in the stomach and small bowel in a patient with a history of allergy.
- Menetrier disease is a protein-losing enteropathy that is often a diagnosis of exclusion. It usually affects the proximal stomach and is pathologically characterized by replacement of parietal cells by hyperplastic epithelial cells, leading to achlorhydria.
- Menetrier disease has a controversial association with gastric carcinoma.
- Gastric Crohn disease is almost always associated with small bowel disease. Usually the distal half of the stomach is affected.
- The earliest pathologic change is the formation of aphthous ulcers.
- Other causes: Gastric varices (from portal hypertension), gastric lymphoma, and submucosal carcinoma are non-inflammatory causes of thickened gastric folds.
3
Q
Hyperplastic Polyp (Inflammatory Polyp)
What is it? In what setting does it occur?
Malignant potential?
A
- A hyperplastic polyp, also known as an inflammatory polyp, is cystic dilation of a gastric gland that develops in response to chronic inflammation. Hyperplastic polyps are almost always benign, with very rare cases of malignant transformation having been reported.
4
Q
What is fundic gland polyposis syndrome?
A
- Fundic gland polyposis syndrome is a variant of familial adenomatous polyposis syndrome that also involves the stomach. In the stomach, most polyps are hyperplastic, but elsewhere in the GI tract, the polyps are adenomatous.
5
Q
Gastric Adenomatous Polyp
What is it?
Malignant potential?
Treatment?
A
- An adenomatous polyp is a neoplastic polyp with malignant potential. There is an elevated risk of malignant transformation to adenocarcinoma if >2 cm in size.
- Adenomatous polyps are usually treated with endoscopic biopsy and polypectomy.
6
Q
Gastric Hamartomatous Polyp
What are they?
What are they associated with?
A
- Hamartomatous polyps are benign polyps usually associated with syndromes such as Peutz-Jeghers, juvenile polyposis, and Cronkhite-Canada syndromes.
7
Q
Cronkhite-Canada Syndrome
What is it?
Etiology?
Malignant potential?
Affected population? Presentation?
A
- Cronkhite–Canada syndrome is a type of non-hereditary hamartomatous polyposis syndrome characterised by rash, alopecia, and watery diarrhea. Characterised by numerous hamartomatous polyps in the digestive tract, with predominant involvement of the stomach, large intestine and, to a lesser extent, small bowel. The exact aetiology is unknown and there is no recognized familial occurrence. Unlike other polyposis syndromes, it is not associated with a malignancy.
- Patients typically present with watery diarrhea and protein losing enteropathy and associated nail atrophy, brownish skin pigmentation, and alopecia
- Polyps are similar to those of juvenile polyposis except that the mucosa among CCS polyps is oedematous and inflammation of the lamina propria usually present.
- Mnemonic: Cranky bald old man brown skin, diarrhea and polyps!
8
Q
What are the kinds of gastric polyps?
A
- Hyperplastic/Inflammatory
- Adenomatous
- Hamartomatous
9
Q
Benign Gastric Masses
A
10
Q
Gastric Lipoma
What is it?
Fluoroscopy distinction between a GIST?
What is diagnostic of a gastric lipoma?
A
- A lipoma is a benign, submucosal, mesenchymal neoplasm.
- At fluoroscopy, a gastric lipoma is indistinguishable from a GIST.
- Fatty attenuation on CT is diagnostic of a lipoma.
11
Q
Gastrointestinal Stromal Tumor (GIST)
What is it?
Where in the GI tract do they occur?
Benign or malignant?
Malignancy of GIST in stomach v other places?
Imaging?
DDx for submucosal gastric mass?
A
- Gastrointestinal stromal tumor - GIST is the most common submucosal gastric tumor.
- The tumor arises from the interstitial cells of Cajal, which are pacemaker cells that drive peristalsis.
- GIST may occur anywhere in the gastrointestinal tract.
- GIST may be benign or malignant, with risk for malignancy determined by size and number of mitoses. Regardless of size and number of mitoses, gastric GIST is less likely to be malignant compared to similar-sized GISTs in the duodenum, jejunum/ileum, or rectum. gastric tumors <2 cm in size are essentially always benign. Larger tumors carry a risk of malignancy as high as 86% for a gastric GIST >10 cm with an elevated mitotic rate.
- Small gastric GISTs are usually asymptomatic, but may be a cause of melena.
- On imaging, a smooth endoluminal surface is characteristic due to its submucosal location. Larger tumors have a tendency to become exophytic, or less commonly to invade the lumen.
- The differential diagnosis of a submucosal gastric mass includes mesenchymal tumors (GIST, fibroma, lipoma, neurofibromas, etc.), carcinoid, and ectopic pancreatic rest.
12
Q
DDx for submucosal gastric mass
A
- The differential diagnosis of a submucosal gastric mass includes
- mesenchymal tumors (GIST, fibroma, lipoma, neurofibromas, etc.)
- carcinoid
- ectopic pancreatic rest.
13
Q
Ectopic Pancreatic Rest
A
- An ectopic pancreatic rest is a focus of heterotopic pancreas in the gastric submucosa.
- The ectopic pancreatic tissue is susceptible to pancreatic diseases, including pancreatitis and carcinoma. on imaging, the classic appearance is an umbilicated submucosal nodule, with the umbilication representing a focus of normal epithelium.
- The ulceration is not always seen, in which case the imaging is of a nonspecific submucosal gastric mass.
14
Q
Gastric Cancer
Presentation?
Cause? Specific risk factors?
Possible pathways of spread?
What is a Krukenburg tumor?
A
- Gastric adenocarcinoma may present either as a mass or as a gastric ulcer.
- Gastric cancer is generally caused by chronic inflammation, with specific risk factors including:
- Ingestion of polycyclic hydrocarbons and nitrosamines (from processed meats).
- Atrophic gastritis.
- Pernicious anemia.
- Post-subtotal gastrectomy.
- Gastric carcinoma may spread locally from the mucosal surface to the serosa, in which case 90% of patients will have omental involvement from trans-serosal spread.
- Lymphatic spread is along lesser curvature -> gastrohepatic ligament and greater curvature.
- A krukenberg tumor is classically described as the metastatic spread of gastric carcinoma to the ovary however, the term has also been used to describe any mucinous metastasis to the ovary.
15
Q
Malignant GIST
Compare to benign GIST
Ease in finding the site of origin?
A
- Malignant GIST tends to be larger than benign GIST, often reaching sizes of greater than 10 cm, with central necrosis.
- Although the tumor begins in the submucosa, it can be difficult to determine the site of origin of large tumors.
16
Q
Gastric Lymphoma
Is solitary, how do you differentiate between lymphoma and gastric CA?
The stomach is a common extranodal site for what kind of lymphoma?
A
- Gastric lymphoma can have a wide variety of presentations. If solitary, lymphoma can mimic gastric carcinoma. To differentiate between lymphoma and gastric carcinoma, the pattern of adenopathy can be helpful. In gastric cancer, adenopathy at or below the level of the renal hila is unusual but occurs more commonly in patients with lymphoma.
- The stomach is a common extranodal site for non-Hodgkin lymphoma.
17
Q
Mets to the Stomach
How common is it?
Most common primary to mets to stomach?
A
- Metastatic disease to the stomach is rare.
- Breast, lung, and melanoma are the most common.
18
Q
Benign Gastric Ulcers
How common are they? What decreases their prevalence?
Typical image findings?
A
- Although less commonly encountered in the modern era of proton pump inhibitors and Helicobacter pylori treatment, benign gastric ulcers tend to have typical imaging findings:
- Radiating gastric folds are smooth and symmetric.
- Ulcer extends beyond the normal contour of the gastric lumen.
- The Hampton line represents nonulcerated acid-resistant mucosa surrounding the ulcer crater.
- Most benign ulcers occur along the lesser curvature of the stomach, although benign ulcers associated with aspirin ingestion can occur in the greater curvature and antrum, which are dependent locations.
19
Q
Malignant Gastric Ulceration
How do you distinguish this from a benign ulcer?
What is the “Carman meniscus”?
A
- Gastric carcinoma may present with malignant ulceration, which can usually be distinguished from a benign ulcer by the following features:
- Asymmetric ulcer crater, with surrounding nodular tissue.
- An abrupt transition between normal gastric wall and surrounding tissue.
- Ulcer crater does not project beyond the expected location of the gastric wall.
- The Carman meniscus sign is considered pathognomonic for tumor. It describes the splaying open of a large, flat malignant ulcer when compression is applied.
20
Q
Overview of Gastric Bypass Surgery
Postoperative anatomy of Roux-en-Y gastric bypass (RYGB)
How does one create the Roux limb?
What is the current favored approach?
What is created to connect the pancreaticobiliary limb?
How does the RYGB lead to weight loss?
A
- A small gastric pouch is created with a volume of approximately 15 to 30 cc by excluding the distal stomach from the path of food.
- The Roux limb is created by transecting the jejunum approximately 35-45 cm distal to the ligament of Treitz, then bringing it up to be anastomosed to the gastric pouch via a narrow gastrojejunostomy stoma.
- The current favored approach for placement of the Roux limb is antecolic (in front of the transverse colon). The Roux limb used to be placed retrocolic, which required the creation of a surgical defect through the transverse mesocolon (mesentery of the transverse colon). A retrocolic Roux limb has a higher risk of a transmesocolic hernia due to the defect in the transverse mesocolon.
- Although the antecolic approach is now more commonly performed, there are many patients who have previously undergone a retrocolic approach.
- A distal side-to-side jejunojejunostomy is created to connect the pancreaticobiliary limb to the jejunum.
- The RYGB leads to weight loss both from early satiety (due to small size of the gastric pouch) and malabsorption (due to surgical bypass of the proximal jejunum).
21
Q
RYGB Complications
Postoperative leak
What is it diagnosed by?
Study of choice?
Where can leaks arise?
A
- Postoperative leak is usually diagnosed by 10 days after surgery.
- An upper GI study with water-soluble contrast is the study of choice if a leak is suspected.
- Leaks may arise from the distal esophagus, gastric pouch, or blind-ending jejunal limb. It is rare for a leak to arise from the distal jejunojejunostomy.
22
Q
What are the RYGB complications?
A
- Postoperative leak
- Gastrogastric fistula
- SBO
- Internal hernia
- Stomal stenosis
- Marginal ulcers
23
Q
RYGB Complications
Gastrogastric Fistula
What is communicating?
Early or late complication?
What can this lead to?
A
- A gastrogastric fistula is a communication between the gastric pouch and the excluded stomach, which may be an early or late complication of RYGB.
- A gastrogastric fistula may be a cause of inadequate weight loss or recurrent weight gain.
24
Q
RYGB Complications
SBO
What is the cause in the acute post op phase?
Treatment?
Cause in case of late presentation?
A
- SBO in the acute postoperative period is most often due to edema or hematoma at the gastrojejunostomy or jejunojejunostomy.
- With a retrocolic Roux limb, edema at the transverse mesocolon defect may also cause obstruction.
- Treatment is usually conservative, with most cases resolving as the edema and/or hematoma resolves.
- A late presentation of small bowel obstruction may be due to internal hernia (more common with laparoscopic surgery) or adhesions (more common with open surgery).
25
RYGB Complications
Internal Hernia
More internal hernias in laparoscopic or open RYGB?
When do they present and how?
What are the characteristic locations?
Imaging features?
* Laparoscopic Roux-en-Y procedures are associated with a higher rate of internal hernias (seen in 2.5% of laparoscopic procedures) compared to open procedures 0.5%). Internal hernias can be difficult to diagnose, both clinically and by imaging.
* Internal hernias usually present within 2 years of bypass and are the most common cause of SBO after a laparoscopic Roux-en-Y.
* Most RYGB-associated internal hernias occur in three characteristic locations.
* The surgically created defect in the mesentery of the transverse colon is the most common site (the transmesocolic hernia), associated with a retrocolic Roux limb.
* Less common sites of internal hernia include Peterson's space (located between the mesentery of the Roux limb and the transverse mesocolon) and the mesenteric defect created by the jejunojejunostomy.
* Imaging features of internal hernia include swirling of the mesentery, a mushroom shape of the mesentery, and/or the presence of small bowel loops posterior to the superior mesenteric artery.
26
RYGB Complcations
Stomal Stenosis
Which ostomy gets stenosed and in what percent of RYGB patients?
What gets dialated?
Treatment?
Which ostomy stenosis requires surgery to treat?
* Narrowing of the gastrojejunostomy stoma may occur in up to 10% of patients, leading to dilation of the pouch and distal esophagus.
* Stomal stenosis is usually treated with endoscopic dilation.
* Narrowing of the distal jejunojejunostomy is much more rare and usually requires surgery.
27
RYGB Complications
Marginal Ulcers
Where do they happen? How often do the occur?
How are they diagnosed? How are they treated?
* The jejunal mucosa adjacent to the gastrojejunal anastomosis is susceptible to gastric secretions, which can cause marginal ulcers in up to 3% of patients.
* A marginal ulcer is diagnosed by upper GI as a thickening and small outpouching of a gastric fold.
* Treatment is conservative.
