Gastric polyps are growths that form on the inner lining of the stomach, representing an abnormal collection of cells that protrude into the stomach cavity. These growths are frequently found during routine upper gastrointestinal examinations. While “polyp” describes a physical projection, the cellular makeup of these lesions varies significantly. Their structure determines their clinical importance, ranging from completely benign findings to lesions that carry an elevated risk for developing cancer.
Defining Gastric Polyps and Their Types
Gastric polyps are categorized by their histological characteristics, describing the specific type of stomach cell they originate from. The most common lesions are classified into three types: Fundic Gland Polyps, Hyperplastic Polyps, and Adenomatous Polyps. This classification determines the appropriate course of action, as each type carries a distinct potential for progression.
Fundic Gland Polyps (FGPs) are the most frequently encountered type, appearing as small, smooth nodules in the fundus and body of the stomach. Microscopically, these growths feature cystic dilation of the normal fundic glands. FGPs are generally considered benign, with a very low likelihood of malignant transformation, especially when they occur sporadically.
Hyperplastic Polyps (HPs) are the second most common type, forming as a reaction to chronic inflammation of the gastric lining. They are characterized by an overgrowth of the foveolar epithelium and often display an inflamed core of connective tissue. While typically not cancerous, a small percentage of HPs, especially those larger than one centimeter, can show abnormal cell growth (dysplasia), which elevates their risk.
Adenomatous Polyps, or adenomas, are significantly less common but have the highest likelihood of becoming cancerous. These growths are characterized by cellular dysplasia, meaning the epithelial cells have an abnormal appearance and growth pattern. The risk of malignancy is directly related to the adenoma’s size and the degree of dysplasia observed. Because they are true neoplastic growths, adenomas are considered precancerous lesions requiring specific attention.
Causes and Associated Risks
Gastric polyp formation is linked to underlying conditions causing chronic irritation or genetic factors leading to uncontrolled cell proliferation. Chronic inflammation of the stomach lining (gastritis) is a major factor in developing Hyperplastic Polyps and Adenomas. The most frequent cause of this persistent inflammation is infection with the bacterium Helicobacter pylori (H. pylori).
The presence of H. pylori triggers a regenerative response in mucosal cells, leading to the excessive tissue growth seen in Hyperplastic Polyps. This infection is also linked to Adenomatous Polyps, especially when inflammation has caused chronic atrophic gastritis. Eradicating the H. pylori infection can often cause Hyperplastic Polyps to regress or disappear.
Long-term use of Proton Pump Inhibitor (PPI) medications, prescribed to reduce stomach acid, is another causative factor. Acid suppression can lead to Fundic Gland Polyps by causing hypergastrinemia, which stimulates fundic gland growth. These PPI-associated polyps are overwhelmingly benign, but their presence marks prolonged medication use.
Rarely, gastric polyps are associated with inherited genetic conditions, such as Familial Adenomatous Polyposis (FAP). Patients with FAP frequently develop multiple Fundic Gland and Adenomatous Polyps throughout the stomach. Since FAP significantly increases the lifetime risk for gastrointestinal malignancies, these polyps require close monitoring.
Detection, Symptoms, and Malignancy Potential
Gastric polyps are frequently asymptomatic, especially when small. Most are discovered incidentally during an upper endoscopy, a procedure examining the esophagus, stomach, and duodenum. When symptoms occur, they are usually related to the polyp’s size or irritation of the stomach lining.
Larger polyps may erode, leading to slow, chronic bleeding that results in iron deficiency anemia, fatigue, and weakness. Rarely, a large polyp can obstruct the passage to the small intestine, causing nausea, vomiting, or fullness. Definitive diagnosis requires a biopsy taken during endoscopy, where a pathologist examines the tissue sample for classification.
The malignancy potential depends highly on the polyp type and the presence of dysplasia. Fundic Gland Polyps have a minimal risk of progressing to cancer (less than 1%), unless associated with a genetic syndrome like FAP. Hyperplastic Polyps carry a low to moderate risk, with malignant change noted primarily in larger lesions or those with severe chronic gastritis.
Adenomatous Polyps pose the greatest threat, as they are inherently precancerous lesions. The potential for malignant transformation rises significantly if the polyp grows larger than two centimeters or shows high-grade dysplasia. The pathologist stratifies cancer risk by looking for dysplasia (abnormal cells). Risk is also increased if the patient has multiple polyps or signs of atrophy in the surrounding stomach lining.
Management and Treatment Options
Management strategy is determined by the polyp’s type, size, and the presence of high-risk features like dysplasia. For small, sporadic Fundic Gland Polyps, watchful waiting or surveillance is appropriate due to their very low cancer risk. Physicians may recommend discontinuing PPI medications if the polyps are PPI-associated, which can sometimes lead to regression.
For Hyperplastic Polyps, management involves addressing the underlying cause, usually eradicating H. pylori infection with antibiotics. This treatment often causes the polyps to shrink or disappear. However, any Hyperplastic Polyp over one centimeter or showing signs of dysplasia is usually removed endoscopically via polypectomy.
Adenomatous Polyps are always recommended for removal, regardless of size, due to their inherent precancerous nature and high risk of progression to gastric cancer. Polypectomy is the standard technique for removing the growth during endoscopy. Patients with adenomas or high-grade dysplasia are placed on a schedule of regular follow-up endoscopies to monitor for recurrence or new lesions.
The decision to remove a polyp also depends on whether it is causing symptoms, such as bleeding or obstruction, even if benign. For polyps associated with rare hereditary syndromes, management is more aggressive, involving frequent endoscopic surveillance and removal of all suspicious growths. This approach ensures that only polyps posing a genuine health risk are targeted for intervention.