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By SRINIVAS SEELA, MD, and AMISH PATEL, MD
The lesser commonly talked about masses of the gastrointestinal tract include gastric polyps. A polyp is an abnormal growth of tissue found projecting from the lining of the body's mucous membranes and similar to polyps found in one's colon during a colonoscopy. Gastric polyps can also be found in your stomach during an upper endoscopy. About 6 percent of people in the United States have gastric polyps, and over 90 percent of those are completely asymptomatic. Symptoms of gastric polyps are very non-specific and include abdominal pain and the development of anemia from chronic bleeding, therefore most polyps end up being diagnosed incidentally during an upper endoscopy. Since there are numerous types of gastric polyps, similar to those of colonic polyps, biopsies are required to rule out pre-cancerous lesions and malignancy as they have no discernable distinguishing features from simple visualization. Biopsies of the surrounding gastric tissue are also recommended to rule out any coexisting abnormalities that may be present. Management of gastric polyps is determined based on the specific histology and cell type confirmed from biopsy, so adequate sampling of the tissue and surrounding areas is imperative. Larger polyps may cause stomach pain, vomiting, losing an unusual amount of weigh and blood in the stool.
Types of Gastric Polyps:
The initial approach to gastric polyps should include an endoscopic and evaluation of polyp histology and the surrounding mucosa.
In the Western world, where the prevalence of the bacteria Helicobacter pylori is relatively lower, the most common type of gastric polyp is a fundic gland polyp. It accounts for 47 percent of polyps in the stomach and is named after its location in the fundus, or the top-most farthest point from the distal opening of the stomach. These are mostly from either the use of proton-pump inhibitors (PPI) like omeprazole, or sporadically on their own. A small subset of these polyps can arise in the context of familial adenomatous polyposis (FAP), which is a rare genetic condition predisposing one to hundreds of polyps throughout the gastrointestinal tract beginning at an early age. Fundic gland polyps occur in 20 to 100 percent of patients with FAP and 11 percent of patients with malignant adenomatous polyposis (it is important to note that they have virtually no potential, less than 1 percent, to grow into a cancerous lesion so the use of PPIs should not be discounted due to gastric polyps alone).
Fundic gland polyp
Fundic polyps that show no signs of abnormal cells do not require any further follow up, but multiple polyps or if abnormal cells are seen, colonoscopy and further genetic testing can be done to rule out hereditary polyposis syndromes. Fundic gland polyps are typically small (0.1 to 0.8 cm), hyperemic, sessile, and have a smooth surface contour. Fundic gland polyps, in contrast with adenomas in patients with FAP, rarely progress to cancer. The possibility of a familial polyposis syndrome should be considered in patients with ?20 polyps.
The second most common type of gastric polyp is a hyperplastic polyp. Although they may arise anywhere, they are typically found in the antrum, or the more distal end where the stomach empties into the small intestine. Hyperplastic polyps can also appear in your stomach. In fact, they're the most common type of stomach polyps. Hyperplastic polyps are usually smooth, dome-shaped, or stalked with an average size ranging from 0.5 to 1.5 cm. Hyperplastic polyps are often multiple and may develop in the antrum, body, fundus or cardia. They're usually benign and rarely develop into cancer. Hyperplastic polyps are strongly correlated with the presence of the Helicobacter pylori bacteria accounting for 80 percent of cases. Due to the strong correlation, hyperplastic polyps do account for the majority of gastric polyps where the prevalence of the H. pylori bacteria is much higher. Most of these polyps will regress on their own after successful eradication of the bacteria. The remainder of the cases arise from chronic gastritis and pernicious anemia. Although still very low, the dysplastic potential of hyperplastic polyps is slightly higher than fundic polyps and can vary between 1-20 percent depending on their histological subtype. The pedunculated subtype that are greater than 1 cm carry the highest risk, therefore all polyps greater than 0.5cm should be resected completely. The risk of malignancy in hyperplastic polyps is increased in polyps >1 cm and pedunculated in shape. Repeat surveillance for the recurrence of these polyps is then recommended at 1 year.
Gastric adenomas are the lesser common of the three types of gastric polyps at 6-10 percent. They are true neoplasms most commonly found in the antrum and are closely related to atrophic gastritis, a change in the cells lining the stomach due to chronic inflammation. Gastric adenomas occur equally in men and women and tend to present most commonly in patients in their 60s and 70s. These are also direct precursors to gastric cancer rendering them most dangerous of the three. Size and histological subtype are also very important in predicting risk for cancer, which varies between 8-59 percent, so resection and pathological analysis is crucial for management and follow up. Polyps with high grade dysplasia require close endoscopic surveillance of shorter intervals than low grade dysplasia ranging from 6 months to 1 year.
One of the more rare types of gastric polyps is a neuroendocrine tumor, also known as a carcinoid. These appear as firm yellowish lesions in the fundus and body, or middle of the stomach. They can appear as solitary lesions or in the context of tumor syndromes such as multiple endocrine neoplasia or MEN. Although typically indolent, a subtype of carcinoids can be aggressive and present with symptoms of episodic flushing, wheezing, nausea, and diarrhea after it has metastasized to the liver. Treatment of the benign lesions is simply resecting the lesion but more invasive gastric resection may be required for the metastatic subtype. Surveillance for these tumors is that of any other gastric lesion, ranging between 6 months to 1 year.
Gastric fundic gland polyp
Gastric polyps are most commonly asymptomatic and benign in nature, making them a common incidental and consequently less significant finding on upper endoscopy. Going forward, the only preventative measure patients can take to prevent gastric polyps may be lifestyle and diet modification to avoid and control chronic gastritis.
Srinivas Seela, MD, finished his fellowship in Gastroenterology at Yale University School of Medicine. He is an Assistant Professor at the University of Central Florida School of Medicine, and a teaching attending physician at both the Florida Hospital Internal Medicine Residency and Family Practice Residence (MD and DO) programs.
Also contributing to the article is Amish Patel, MD.
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