Management of Gastric Polyps: A Pathology-Based Guide for Gastroenterologists
Carmack SW, Genta RM, Graham DY, Lauwers GY
Nat Rev Gastroenterol Hepatol. 2009;6:331-341
The discovery of gastric polyps during an endoscopic examination of the stomach is a relatively common occurrence for gastroenterologists. In fact, a diverse array of polyps and polypoid lesions are found in the stomach. However, there is a paucity of specific analytic and practical clinical guidance for the management of such lesions. A recent article by Carmack and colleagues is an outstanding review of the management of gastric polyps and, as such, provides excellent guidance for endoscopists who encounter these lesions. What follows is a capitulation and highlighted summary of the article.
Fundic Gland Polyp
In the western world, fundic gland polyps are the most common type of polyps detected by endoscopy. These lesions are typically less than 0.5 cm in size, sessile, and smooth and glassy in appearance. They may occur sporadically (almost always in the absence of Helicobacter pylori) in patients who have familial polyposis, and they are particularly common in patients who take proton pump inhibitors (PPIs) on a long-term basis.
Both the sporadic and PPI-related types of fundic gland polyps have an extremely low malignant potential. The PPI-related lesions may regress once use of the PPI is discontinued. Larger polyps (>1 cm) should be removed endoscopically, and if the patient is taking a PPI, discontinuation of the PPI should be considered. A polyp associated with familial polyposis carries a defined 30% to 50% risk of developing dysplasia. Risk factors for dysplasia include polyps that are larger than 1 cm, increased severity of duodenal polyposis, and antral gastritis. Although no guidance is offered regarding optimal intervals for follow-up examinations, regular surveillance by endoscopy is recommended.
When multiple fundic gland polyps are evident in younger patients, evaluation for familial polyposis should be considered.
Hyperplastic polyps are caused by an inflamed and often atrophic gastric mucosa. In the western world, the prevalence is declining, in part because of the declining prevalence of H pylori. These polyps typically occur in the antrum and often in presentations of multiple lesions. They have a smooth, dome-shaped appearance. Hyperplastic polyps can be large in size, and patients may present with chronic blood loss or even gastric obstruction.
Elimination of the underlying cause, such as H pylori infection, typically results in polyp regression. When encountered as isolated or polypoid lesions at gastrectomy sites, hyperplastic polyps have a low but defined neoplastic risk. The overall prevalence of dysplasia is estimated at less than 2%; however, the risk is higher if polyps exceed 2 cm in size. For this reason, large polyps must be completely excised. In the absence of dysplasia, the optimal management of small polyps located at gastrectomy sites was not defined.
The diagnosis of a hyperplastic polyp of any size requires a full set of gastric biopsies to determine gastric mucosal characteristics for purposes of topographic mapping. If H pylori infection is present, eradication is warranted, and follow-up endoscopy is appropriate to confirm cure of the H pylori infection as well as regression of the remaining polyps. If extensive gastric atrophy and metaplasia are found, a surveillance plan should be implemented (although no specific intervals were defined).
Adenomatous polyps occur sporadically or in association with familial polyposis. Typically, these polyps are circumscribed and can be pedunculated or sessile in form. In addition, they can have dysplastic epithelium that does not invade the lamina propria. These polyps are most often associated with chronic atrophic gastric metaplasia, and they have a defined cancer risk. The larger the polyp, the greater the risk that the polyp contains cancer. In polyps larger than 2 cm, the risk for cancer is as high as 50%.
Endoscopic resection is appropriate, and surveillance follow-up at 1 year is recommended. Gastric mapping is useful to determine whether there is atrophic gastric metaplasia, which would be an indication for surveillance.
A synchronous adenocarcinoma has been found in another area of the stomach in up to 30% of patients who have an adenomatous polyp. For this reason, careful inspection of the entire stomach is warranted when adenomatous polyps are identified.
Polyposis syndromes, which are characterized by the growth of multiple polyps, are rare and include juvenile polyposis, Cronkite-Canada syndrome, Peutz-Jeghers syndrome, and Cowden's disease. Hamartomatous polyps may be present in all of these syndromes. Adenomatous polyps, as mentioned, may be found in familial polyposis.
There is no defined guideline for the care of patients who have familial polyposis, but it is suggested that endoscopic surveillance be performed at 30 years of age and at 3-year intervals. Patients who have large numbers of polyps should undergo surveillance annually.
Peutz-Jeghers syndrome is associated with an estimated lifetime risk for gastric cancer of approximately 30%. For patients who have this syndrome, endoscopic surveillance should begin at 18 years of age and continue at 2- to 3-year intervals.
Juvenile polyposis has a lifetime associated risk for gastric cancer of 15% to 20%, and gastric surveillance is recommended at 1- to 2-year intervals.
For Cronkite-Canada syndrome, the focus should be on pharmacologic therapy and surgical resection.
In Cowden's disease, there is no association with gastric malignancy. Instead, surveillance should focus on breast and thyroid cancer screening.
Inflammatory Fibroid Polyps
Inflammatory fibroid polyps, also known as Vanek tumors, are rare, representing fewer than 1% of all gastric polyps. These tumors are rarely symptomatic but can be associated with bleeding or gastric outlet obstruction.
Most inflammatory fibroid polyps are found incidentally and do not recur. No surveillance is recommended.
Inflammatory fibroid lesions typically have massive eosinophilic infiltrates and are occasionally --and incorrectly-- called eosinophilic granulomas.
Gastrointestinal Stromal Tumor
Gastrointestinal stromal tumors (GISTs) make up 1% to 3 % of gastric neoplasms and occur more frequently in men than in women. GISTs are typically located in the fundus. Because these lesions are submucosal, mucosal biopsy proves inadequate as a diagnostic assay in that results are typically normal. Endoscopic ultrasonography-guided biopsy with fine-needle aspiration provides the best tissue sample for diagnosis. GISTs are categorized as having malignant potential ranging from low risk to high risk on the basis of polyp size and level of mitotic activity.
All GISTs should be regarded as having neoplastic potential. Up to 50% of patients have metastatic disease (typically hepatic) on presentation. Surgical resection is recommended for lesions larger than 2 cm. Endoscopic resection is an option for smaller GISTs.
GISTs have a unique immunostaining characteristic that allows a specific diagnosis: The stain for the KIT gene product CD117 is positive in 95% of cases. Endoscopic removal of GISTs is controversial because of reports of positive resection margins and tumor spillage.
There are 3 types of gastric carcinoid tumors. Type 1 carcinoid tumors account for 65% to 80% of all gastric carcinoids and are more common in women than in men. They are often associated with chronic autoimmune atrophic gastritis and pernicious anemia. Type 2 carcinoid tumors account for 3% to 15% of gastric carcinoids and are associated with Zollinger-Ellison syndrome and multiple endocrine neoplasia. Type 3 carcinoid tumors are sporadic, account for approximately 20% of gastric lesions, and occur more frequently in men than in women.
Types 1 and 2 carcinoids are associated with the development of hypergastrinemia. These related carcinoids are typically multiple, broad-based, firm, yellowish lesions that are located in the fundus or gastric body. They tend to be smaller than 2 cm. In contrast, the sporadic type 3 carcinoids are typically single, prepyloric, and larger than 2 cm.
The overall prognosis depends on the type of carcinoid encountered. Local excision is recommended, if possible. Type 1 carcinoids rarely metastasize. However, antrectomy should be considered if multiple lesions are present. Type 2 carcinoids should be managed by endoscopic polypectomy followed by regular surveillance if the underlying gastrinoma cannot be removed. Type 3 lesions have a propensity for invasion and metastasis. Gastrectomy is the therapy of choice, although the 5-year survival rate is still less than 50%.
The carcinoid syndrome when associated with gastric carcinoids is present almost exclusively in patients with type 3 lesions.
Pancreatic heterotopia has 2 gastric presentations. One is seen as a submucosal nodular involvement (single or multiple) at the esophagogastric junction; on histologic examination, pancreatic tissue is evident. This type of pancreatic heterotopia is reportedly found in 5% to 15 % of patients who undergo endoscopy for gastroesophageal reflux disease and have a biopsy sample taken from the esophagogastric junction. The second type of pancreatic heterotopia is a submucosal nodular lesion located in the antrum and prepyloric area. Characteristic but not typical of this second type of nodule is a central dimple, and histologic features resemble normal pancreatic tissue.
Both types of pancreatic heterotopia constitute a benign and asymptomatic condition. No therapy is warranted.
Ductal adenocarcinoma, islet-cell tumors, and pancreatitis can arise in heterotopic pancreas tissue, but the rarity of these diagnoses suggests that neither surgical excision nor endoscopic surveillance is warranted. However, biopsy of these umbilicated lesions is advised because malignant tumors having this appearance (eg, breast cancer, lung cancer, and melanoma) can involve the stomach.
Medscape Gastroenterology © 2009 Medscape, LLC
Cite this: David A. Johnson. How to Manage Gastric Polyps Discovered on Endoscopy - Medscape - Aug 11, 2009.