eMedicine Specialties > General Surgery > Abdomen

Benign Gastric Tumors

Andres Fleury, MD, Clinical Assistant Instructor, Department of Surgery, State University of New York Upstate Medical University; Resident, Department of Surgery, Robert Packer Hospital
Burt Cagir, MD, FACS, Assistant Professor of Surgery, State University of New York, Upstate Medical Center; Consulting Staff, Director of Surgical Research, Robert Packer Hospital; Associate Program Director, Department of Surgery, Guthrie Clinic; Michel M Murr, MD, Professor, Department of Surgery, Director of Bariatric Surgery, University of South Florida

Updated: Nov 26, 2008

Introduction

Background

With the advent of modern techniques and the widespread use of gastric endoscopy, benign gastric wall lesions are now diagnosed more frequently and can be studied using the tissue obtained by biopsy or polypectomy. In the past, the diagnosis of gastric tumors was based on x-ray examination, but, in 1922, Schendler was the first to make an endoscopic-based diagnosis.¹

Pathophysiology

All layers of the stomach wall have the potential to produce tumorous growths. In 40% of patients with benign gastric tumors, the lesions are mucosal tumors. Another 60% are nonmucosal based. Gastric polyps are defined as luminal lesions projecting above the plane of the mucosal surface and are relatively frequent in routine pathology practice. Various subtypes of gastric polyps are recognized and divided into nonneoplastic and neoplastic and are also further classified by their association with polyposis syndromes.²

The following is a classification of benign gastric tumors (see Media file 2).

1.- Mucosal tumors

         1.1.- Nonneoplastic polyps
            1.1.1.- Not associated with polyposis syndromes
            1.1.1.1 Hyperplastic polyps
            1.1.1.2 Inflammatory fibroid polyp (eosinophilic granuloma - Vanek tumor)
            1.1.1.3 Xanthoma/xanthelasma
            1.1.1.4 Ectopic pancreas

            1.1.2.- Associated with polyposis syndromes
            1.1.2.1 Hamartomatous polyp (Peutz-Jeghers syndrome)
            1.1.2.2 Juvenile polyps
            1.1.2.3 Cowden disease
            1.1.2.4 Cronkhite-Canada syndrome
            1.1.2.5 Gardner syndrome

         1.2.- Neoplastic polyps
            1.2.1 Fundic gland polyp
            1.2.2 Adenomatous polyp
            1.2.3 Gastric carcinoid

2.- Nonmucosal tumors

         2.1.- Mesenchymal
            2.1.1 Gastrointestinal stromal tumor (GIST)
            2.1.2 Lipoma
            2.1.3 Fibroma
            2.1.4 Glomus tumor

         2.2.- Vascular
            2.2.1 Hemangioma
            2.2.2 Lymphangioma

Frequency

United States

Benign tumors of the stomach are uncommon, with an incidence of 0.4% in autopsy series and 3-5% in upper endoscopic series, most of them performed for unrelated reasons. Polyps account for 3.1% of all gastric tumors, and their frequency increases to almost 90% of benign gastric tumors (Shackelford, 2007).

They can become inflamed or eroded, but bleeding still remains unusual. Large distal lesions have been associated with symptoms of gastric outlet obstruction.²

Mortality/Morbidity

The majority of benign gastric tumors are asymptomatic, but, very rarely, they present with epigastric pain, gastric outlet obstruction, and bleeding. Adenomatous polyps have a truly neoplastic behavior with the potential for the development of malignancy. Also, gastrointestinal stromal tumors (GISTs) have different behavioral patterns, ranging from benign to malignant.

Race

There is no difference in distribution by race.

Sex

Sex distribution depends on the type of tumor and will be discussed in subsequent sections.

Age

Age distribution depends on the type of tumor and will be discussed in subsequent sections.

Clinical

History

Many tumors are found incidentally on gastroscopy.
Small tumors are usually asymptomatic, but larger tumors can ulcerate and cause occult bleeding and anemia.
Large antral tumors cause intermittent gastric outlet obstruction, as manifested by nausea, vomiting, and early satiety. If ulcerated, these tumors may cause epigastric pain similar to a peptic ulcer.

Physical

Physical findings are not specific, except for underlying conditions, such as Peutz-Jeghers syndrome, in which patients may have abnormal pigmentation of the oral mucosa, lips, and digits.
An abdominal mass may be palpable.
Palpation may elicit abdominal tenderness.

Causes

The etiology of benign tumors varies depending on the type of tumor and associated pathology and will be discussed in detail in subsequent sections.

Differential Diagnoses

Achlorhydria
Arteriovenous Malformations
Gastric Ulcers

Workup

Laboratory Studies

Findings on laboratory serum tests are nonspecific.

Imaging Studies

Air-contrast studies of the stomach are sensitive in delineating mucosal details and lesions.
Lesions are often found incidentally by computerized tomography scan or other radiological evaluations of the upper gastrointestinal tract.

Procedures

Endoscopy has become more common for both diagnostic and therapeutic purposes. Endoscopic findings that suggest malignancy include red coloring, the presence of surface erosions, and the absence of a pedicle. If small superficial lesions are removed endoscopically, follow-up should include a regular annual endoscopy.
Endoscopic biopsies are difficult to interpret and may be misleading because deep layers of the stomach wall or the tumor are not sampled. Snare biopsies that retrieve the whole specimen are preferred whenever technically possible.
Endoscopic ultrasound (EUS) is helpful in broad-based lesions, where the relationship of the tumor to the layers of the stomach is important. Disruption of the normal sonographic appearance of 5 layers on EUS may signify invasion.

Histologic Findings

Hyperplastic polyps

There is marked elongation of the pits with branching, resulting in a corkscrew appearance or in cystic dilatation of foveolae. Also, there is an excess of lamina propria with plasma cells, lymphocytes, eosinophils, mast cells, macrophages, and neutrophils. The gastric glands do not normally participate in the formation of the polyps. The surface may be ulcerated and inflamed with regenerative atypia. There may also be invagination of the surface mucosa with budding.²

Inflammatory fibroid polyps

These polyps are centered on the submucosa. Small, thin walled vessels surrounded by spindle cells are arranged in an "onion-skin" pattern. CD 34 positive and c-kit negative.²

Hamartomatous polyps of the Peutz-Jeghers type

Gastric mucosa is less frequently involved than the small bowel and the colon. They are composed by hyperplastic glands separated by branching cores of smooth muscle with atrophy of deep glandular components. Dysplasia is very uncommon.²

Juvenile polyps

These polyps are very rare and are usually associated with juvenile polyposis. They are composed of edematous and inflamed mucosa with tortuosity of the foveolar zones and are easily confused with hyperplastic polyps. There is an association with an increased risk of cancer.²

Gastric polyps in Cowden Disease

The foveolar glands are enlarged and elongated. Smooth muscle fibers are intermingled within the mucosal components and the cystic structures extend into the submucosa.²

Gastric polyps in Cronkhite-Canada syndrome

These polyps are usually associated with lesions in other parts of the GI tract. They are indistinguishable from juvenile polyps and hyperplastic polyps, and they are diagnosed if in the presence of alopecia, nail atrophy, or hyperpigmentation.²

Fundic gland polyps

These are dilated glands lined by fundic epithelium mixed with normal glands. There is usually no inflammation or atypia, but some disordered muscle fibers may be seen.²

Adenomatous polyps

They are composed of tubules or villi of dysplastic epithelium with some degree of intestinal-type differentiation. They can be low grade or high grade, based on the degree of dysplasia. The risk of malignancy is related to the size, the degree of dysplasia, and the villosity of the growth pattern. Forty percent to 50% of lesions greater than 2 cm contain carcinomatous transformation.²

Gastric carcinoids

Gastric carcinoids are very rare, representing less than 0.5% of gastric neoplasms, and are seen in 3 different settings: autoimmune atrophic gastritis, Zollinger Ellison syndrome, and MEN-1 syndrome, or they may be seen sporadically. They are usually broad-based, yellowish polypoid lesions overlined by normal mucosa. Chromogranin A is positive, but chromogranin B is usually negative. Synaptophysin is positive in 50% of cases.²

Staging

Depends upon the type of tumor

Treatment

Medical Care

From the large variety of gastric tumors, the GIST is the only type that has a real systemic medical therapy because of the expression of KIT (tyrosine kinase receptor).

Imatinib mesylate (Gleevec) is a small-molecule receptor inhibitor that targets KIT. Clinical trials have shown partial response rates of 40-69% progression-free survival in patients treated with imatinib for advanced, recurrent, or metastatic GISTs. It has been used in the preoperative treatment of patients with GISTs that are imatinib-responsive to decrease tumor size before surgical resection.³

Surgical Care

Gastric polyps

Gastric polyps include hyperplastic polyps, adenomatous polyps, fundic gland polyps, and inflammatory fibroid polyps. Endoscopic excision of gastric polyps provides a minimally invasive approach to diagnosis and treatment. Polyps less than 2 cm are easily snared. Larger polyps or sessile polyps are best removed operatively to obtain a clear margin and complete removal. Occasionally, staged piecemeal endoscopic removal can be performed in patients with severe comorbidities. Wide, local, or segmental resection of the stomach may be performed for multiple polyps, depending on their histology and location. Gastrectomy is justified in patients with diffuse involvement of the stomach by polyps, which can make detection of a synchronous focus of cancer difficult.

Hyperplastic polyps are by far the most common histologic type, and they can vary in location, number, and size. Most are less than 2 cm. Although these polyps harbor no malignancy, they may be accompanied by atrophic gastritis, which predisposes the nonpolypoid mucosa to malignant transformation. Multiple hyperplastic polyps are found in Ménétrier disease. The histology of these polyps is different from that of colorectal polyps in that it shows submucosal edema and faveolar hyperplasia.

Adenomatous polyps (tubular and villous) are usually solitary lesions in the antrum. They have atypical cells and are associated with adenocarcinoma of the stomach. This association is strongest in polyps greater than 2 cm in diameter. The overall incidence of complete malignant transformation in adenomatous polyps is about 3.4%.

Fundic gland polyps contain microcysts that are lined by fundic-type parietal and chief cells, and they are located in the fundus and body of the stomach. They are common in familial polyposis syndromes and have no malignant potential.

Inflammatory fibroid polyps are benign spindle cell tumors that are infiltrated by eosinophils, but they are not associated with a systemic allergic reaction or eosinophilia. Excision of inflammatory fibroid polyps is indicated because of their propensity to enlarge and cause obstruction.

Polyposis syndromes

Sometimes polyps in the stomach are associated with polyposis syndromes. These syndromes include juvenile polyposis, Gardner, Peutz-Jeghers, and Cronkhite-Canada syndromes.

Juvenile polyposis and Cronkhite-Canada syndrome rarely result in gastric cancer.

Peutz-Jeghers syndrome involves gastric hamartomatous polyps. The gastric involvement is generally less than that observed in the small intestine. These polyps can bleed or obstruct the antrum and should be treated accordingly. Although patients with Peutz-Jeghers syndrome may occasionally develop gastric cancer, other nongastrointestinal cancers are more common.

Adenomatous polyps of the stomach and duodenum develop in 50% of cases of familial polyposis and Gardner syndrome. Polyps are usually multiple, and they are best treated endoscopically. Multiple treatments every 3-4 months may be necessary for complete eradication. Routine surveillance endoscopy should be instituted as a life-long program. Patients with Gardner syndrome develop adenomatous polyps in the duodenum as well as in the stomach and should undergo routine esophagogastroduodenoscopy.

Nonmucosal intramural tumors

Leiomyomas formerly comprised the most common submucosal tumors of the stomach. Many tumors formally designated as leiomyomas (and leiomyosarcomas) are now classified as gastrointestinal stromal tumors (GISTs) and are believed to arise from interstitial cells of Cajal rather than from smooth muscle per se. The overall incidence of GISTs is approximately 4 per 1 million in the general population and can be found throughout the GI tract from the esophagus to the rectum; however, the stomach is the most common site.

Most of the patients with GISTs are asymptomatic, but anemia and acute GI bleeding from tumor ulceration can occur.

There is a spectrum from benign to malignant. Histologic characteristics, such as the number of mitotic figures, tumor necrosis, and cellularity, are indicators of malignancy. The only reliable indicator of malignancy in these and other GISTs is evidence of extragastric spread. Lymphatic spread is rare, but hematogenous spread to the liver and the lungs is more common. These tumors can cause symptoms by obstruction, ulceration, and blood loss or by compressing adjacent organs. They appear as large submucosal lesions on endoscopy, and endoscopic biopsies are invariably not deep enough to be of any diagnostic value.

As defined by the GIST Consensus Conference, the goal of treatment should be complete resection of visible as well as microscopic disease, while avoiding tumor rupture and obtaining negative margins. Because of the adequacy of a narrow margin of resection, there has been significant interest in developing operative techniques that accomplish effective tumor resection but minimize morbidity, preserving stomach parenchyma, and reduce medical costs. Minimally invasive surgery has been proven to be effective for GIST resection with shorter hospital stays and comparable operating room time and blood loss when compared to open techniques.⁴

The GIST Consensus Conference recommended laparoscopic resection for tumors less than 2 cm, and recent studies found laparoscopic treatment to be safe and effective in tumors averaging 4.4 cm.^5,6 The pathological phenotype and especially the tumor mitosis correlate significantly with patient survival even if the resected tumor size was relatively small.⁷

For GISTs located in the fundus, along the greater curvature, a laparoscopic gastric wedge resection may be beneficial. Tumors in the lesser curvature are less likely to be effectively resected via laparoscopy because of the limited mobility of the stomach in this area. For GE junction tumors, the laparoscopic transgastric procedure can be used successfully.⁵

Lipomas are rare submucosal tumors that are sometimes indistinguishable from GISTs. They represent deposits of adipose tissue in the wall of the stomach, usually in the submucosa. They may cause symptoms when exceeding 2 cm in size. The standard treatment is surgical resection, but endoscopic treatment has been proposed for lesions less than 2 cm.⁸

Fibroma and fibromyoma are most commonly observed as small intramural or subserosal lesions during the course of an unrelated surgery. Removal is warranted to confirm their benign nature.

Ectopic pancreas can occasionally cause symptoms by obstructing the pylorus or bleeding. Characteristic findings on endoscopy include a nipplelike appearance and a central ductal orifice. Histologic evaluation can reveal acute and chronic pancreatitis and cystic dilatation of the duct. Asymptomatic lesions require no further treatment. Local full-thickness excision of the gastric wall is adequate for complete removal.

Cystic tumors can be mucocele or intramucosal, and they are the most common benign cystic lesion of the stomach. They develop as a result of obstruction of mucous-secreting glands. Duplication cysts are congenital lesions that share a common wall with the stomach but do not communicate with the lumen. They enlarge because of trapped secretions, resulting in symptoms of obstruction. Treatment of duplication cysts is operative excision.

Consultations

No consultations are indicated.

Diet

No specific diet pattern has been established as etiology or as treatment of benign gastric tumors.

Activity

No relationship exists between activity and tumor growth.

Follow-up

Further Outpatient Care

In familial polyposis and Gardner syndrome, routine surveillance endoscopy should be instituted as a life-long program.

Prognosis

See Medical Care.

Multimedia

Media file 1: Benign gastric tumors. CT scan of the abdomen showing a large GIST in the wall of the lesser curvature of the stomach.

Media file 2: Classification of benign gastric tumors.

Media file 3: Upper endoscopy showing multiple gastric polyps.

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Keywords

benign gastric tumors, benign gastric tumor, benign stomach tumors, stomach polyps, gastric wall lesions, hyperplastic polyps, adenomatous polyps, fundic gland polyps, inflammatory fibroid polyps, juvenile polyps, familial polyposis, syndromes, Peutz-Jeghers syndrome, nonmucosal intramural tumors, leiomyoma, fibroma and fibromyoma, lipoma, ectopic pancreas, neurogenic and vascular tumors, cystic tumors, duplication cyst, mucocele

Contributor Information and Disclosures

Author

Andres Fleury, MD, Clinical Assistant Instructor, Department of Surgery, State University of New York Upstate Medical University; Resident, Department of Surgery, Robert Packer Hospital
Andres Fleury, MD is a member of the following medical societies: American College of Surgeons, American Medical Association, and National Hispanic Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Burt Cagir, MD, FACS, Assistant Professor of Surgery, State University of New York, Upstate Medical Center; Consulting Staff, Director of Surgical Research, Robert Packer Hospital; Associate Program Director, Department of Surgery, Guthrie Clinic
Burt Cagir, MD, FACS is a member of the following medical societies: American College of Surgeons, American Medical Association, and Society for Surgery of the Alimentary Tract
Disclosure: Nothing to disclose.

Michel M Murr, MD, Professor, Department of Surgery, Director of Bariatric Surgery, University of South Florida
Michel M Murr, MD is a member of the following medical societies: American College of Surgeons, American Hepato-Pancreato-Biliary Association, American Society for Bariatric Surgery, Association for Academic Surgery, International College of Surgeons US Section, Society for Surgery of the Alimentary Tract, and Southeastern Surgical Congress
Disclosure: Tyco Consulting fee Consulting

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

David L Morris, MD, PhD, Professor, Department of Surgery, St George Hospital, University of New South Wales, Australia
Disclosure: Nothing to disclose.

CME Editor

Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy
Paolo Zamboni, MD is a member of the following medical societies: American Venous Forum and New York Academy of Sciences
Disclosure: Nothing to disclose.

Chief Editor

John Geibel, MD, DSc, MA, Vice Chairman, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital
John Geibel, MD, DSc, MA is a member of the following medical societies: American Gastroenterological Association, American Physiological Society, American Society of Nephrology, Association for Academic Surgery, International Society of Nephrology, New York Academy of Sciences, and Society for Surgery of the Alimentary Tract
Disclosure: AMGEN Royalty Other; AstraZeneca Grant/research funds Other

Acknowledgments

To my wife, Mariana, for her support and to my two angels, Diego and Sofia, for their patience.

The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Carol E H Scott-Conner, MD, PhD, to the development and writing of this article.

Further Reading