Summary
Benign lesions of the stomach and small intestine are diverse and include epithelial polyps and subepithelial lesions. These lesions are often discovered incidentally during endoscopy. Causes vary, with some polyps arising from chronic gastric mucosal injury due to conditions such as Helicobacter pylori infection or autoimmune gastritis, while others are associated with chronic proton pump inhibitor (PPI) therapy or hereditary polyposis syndromes. Most lesions are asymptomatic, but large growths can cause symptoms such as gastrointestinal bleeding, anemia, abdominal pain, and intestinal obstruction. Diagnosis is primarily made via esophagogastroduodenoscopy (EGD), which allows for direct visualization; endoscopic ultrasound (EUS) is particularly useful for evaluating subepithelial lesions. Biopsy with histopathology is often required to confirm the diagnosis and differentiate between lesion types. Management is tailored to the specific lesion and may include conservative monitoring, eradication of H. pylori, or endoscopic or surgical resection of symptomatic, large, or premalignant lesions. While many lesions are benign, some, particularly gastric and duodenal adenomas, carry a significant risk of malignant transformation into adenocarcinoma.
Overview
| Overview of benign lesions of the stomach and small intestine | ||||
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| Lesions | Etiology | Clinical features | Diagnostics | Management |
| Fundic gland polyps |
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| Hyperplastic gastric polyps |
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| Gastric adenomas |
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| Gastric leiomyomas |
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| Nonampullary duodenal adenomas |
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| Small intestine hemangiomas |
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| Small intestine lipomas |
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Fundic gland polyp
Definition [1]
Fundic gland polyps (FGPs) are a type of benign gastric epithelial polyp (GEP) located in the gastric fundus and/or body; they occur sporadically or in association with hereditary polyposis syndromes.
Epidemiology
- Prevalence: most common type of GEP [2]
- Sex: ♀ > ♂ [1]
- Age: most commonly occurs in individuals > 50 years of age [1]
Classification [1][2]
-
Sporadic FGP
- Occurs in the absence of polyposis syndromes
- Associated with chronic PPI therapy
- Not considered premalignant
-
FAP-associated FGP
- Caused by mutations in Wnt pathway genes such as APC and CTNNB1
- Lesions are considered preneoplastic; the risk of dysplasia and gastric adenocarcinoma is higher than for sporadic FGPs.
Clinical features [1]
- Usually asymptomatic and found incidentally
- Symptoms, if present, are usually due to coexisting gastric pathology (e.g., gastritis).
- Obstruction from large polyps is very rare.
Diagnosis [1][2][3]
Diagnosis is primarily made based on EGD findings.
EGD
- Location: gastric fundus and/or body
- Morphology: sessile, smooth, and dome-shaped with a translucent surface
- Color: pale or similar to the surrounding mucosa
- Size: small (< 5–10 mm)
- Number: solitary or multiple
Biopsy
- Indications [1][3]
- Histopathologic findings: cystically dilated oxyntic glands lined by chief and parietal cells with minimal inflammation
During initial endoscopic evaluation, any GEP that is not an obvious FGP should be biopsied for histopathologic assessment. [2]
Differential diagnoses [2][3]
The differential diagnosis includes other GEPs, e.g.:
- Hyperplastic gastric polyps
- Gastric adenomas
Management
Sporadic FGP [1][3]
- Conservative management is appropriate in most cases.
- Endoscopic surveillance is not indicated due to the low risk of malignant transformation.
- Consider endoscopic resection if > 1 cm or atypical features are present.
- Review the need for PPI therapy in patients with multiple FGPs.
FAP-associated FGP [4]
- Endoscopic surveillance is recommended due to the increased risk of dysplasia and gastric adenocarcinoma.
- Endoscopic therapy includes:
- Resection of all polyps > 1 cm
- Extensive polyp sampling and debulking of large polyposis mounds
Hyperplastic gastric polyp
Definition [2][3]
Hyperplastic gastric polyps (HGPs) are a type of benign gastric epithelial polyp associated with chronic gastric mucosal injury; they are considered premalignant lesions.
Epidemiology
- Prevalence: second most common type of GEP [2]
- Geographic variation: Prevalence increases with prevalence of H. pylori infection. [2]
Etiology [2][3]
HGPs are typically associated with chronic gastritis caused by conditions such as:
Clinical features [2][3]
- Typically asymptomatic and found incidentally
- Symptoms, if present, are usually due to coexisting gastric pathology (e.g., gastritis).
Diagnosis [2][3]
Diagnosis is primarily made based on EGD findings and histopathologic assessment.
EGD
- Location: gastric antrum
- Morphology: smooth, dome-shaped with a red surface and occasional white exudates
- Size: 0.5–1.5 cm, but may be larger
- Number: usually solitary or present in small numbers
Biopsy
- Required to confirm the diagnosis
- The surrounding mucosa should be evaluated for background pathology (e.g., atrophic gastritis, gastric intestinal metaplasia, H. pylori infection).
Differential diagnoses [2][3]
- Fundic gland polyps
- Gastric adenomas
- Gastric neuroendocrine tumors (NETs)
Management [2][3]
- Treat H. pylori infection if present. [3]
- Reassess after H. pylori eradication therapy to determine whether resection is needed.
- Endoscopic resection is recommended for lesions > 1 cm.
- The background mucosal pathology determines the need for endoscopic surveillance.
Complications
Gastric adenoma
Definition
Gastric adenomas are a type of gastric epithelial neoplasm associated with chronic gastric mucosal injury (e.g., due to H. pylori gastritis or autoimmune gastritis) or hereditary polyposis syndromes.
Epidemiology [2]
- Prevalence: third most common type of GEP
- Geographic variation: Prevalence increases with prevalence of H. pylori infection.
Etiology [2][3]
- H. pylori infection
- Autoimmune gastritis
- Gastric intestinal metaplasia
- Hereditary polyposis syndromes
Clinical features [2][3]
- Typically asymptomatic and found incidentally
- Symptoms, if present, are usually due to coexisting gastric pathology (e.g., gastritis).
Diagnosis [2][3]
Diagnosis is primarily made based on EGD findings and histopathologic assessment.
EGD
- Location: gastric antrum and/or incisura angularis
- Morphology: pedunculated or sessile, velvety pink, and lobulated
- Size: usually < 2 cm
- Number: solitary
Biopsy
- Required to confirm the diagnosis and determine the grade of dysplasia
- The surrounding mucosa should be evaluated for background pathology (e.g., atrophic gastritis, GIM, H. pylori infection).
Differential diagnoses [2][3]
- Fundic gland polyps
- Hyperplastic gastric polyps
- Gastric NETs
- Gastric adenocarcinoma (early)
Management [2][3]
- Treat H. pylori infection if present.
- All gastric adenomas should be endoscopically resected if feasible; options include: [2]
- Endoscopic mucosal resection for lesions ≤ 10 mm
- Endoscopic submucosal dissection is preferred for larger or sessile lesions.
- Follow-up EGD within 12 months of complete endoscopic resection is advised.
- The background mucosal pathology determines subsequent endoscopic surveillance.
Complications
- Malignant transformation: Approx. 50% of gastric adenomas > 2 cm contain foci of adenocarcinoma. [3]
- Synchronous gastric adenocarcinoma: found in up to 30% of individuals with gastric adenomas [3]
Gastric leiomyoma
Definition [5][6]
Gastric leiomyomas are benign, sporadic subepithelial lesions arising from smooth muscle in the muscularis mucosa or muscularis propria. GI leiomyomas are most commonly located in the esophagus but can also occur in the stomach.
Clinical features [5][6]
- Typically asymptomatic and found incidentally
- Symptomatic lesions may cause:
- Abdominal pain
- Clinical features of gastrointestinal bleeding (overt or occult)
- Features of anemia
Diagnosis [5][6]
The primary goal is to differentiate between leiomyomas and gastrointestinal stromal tumors (GISTs).
EGD with EUS
- Smooth, subepithelial lesions with normal overlying mucosa
- EUS is the imaging modality of choice for initial evaluation if a subepithelial lesion is suspected on EGD.
- Findings
- Layer of origin: muscularis mucosa, submucosa, or muscularis propria
- Echogenicity: hypoechoic
- Contrast-enhanced EUS
- Helps distinguish leiomyomas from GISTs with high accuracy (> 95%) [6]
- Findings: Leiomyomas show hypoenhancement; GISTs typically show hyperenhancement.
Biopsy
- Required to confirm the diagnosis
- EUS-guided fine-needle biopsy or fine-needle aspiration is the preferred sampling method.
- Histopathologic findings
- Microscopy: spindle cells and/or epithelioid cells
-
Immunohistochemistry for differentiation from GIST
- Positive for desmin and smooth muscle actin
- Negative for CD117 and CD34
Differential diagnoses [5]
- GISTs
- Schwannomas
- Gastric NETs
- Metastasis
- Ectopic pancreas
Management [5]
Management is symptom-based; routine surveillance is not indicated.
- Asymptomatic: no resection required
- Symptomatic: Resection may be considered; choice of resection method is based on lesion characteristics and available local expertise.
Complications [5][6]
Large or ulcerated leiomyomas can result in:
Nonampullary duodenal adenoma
Definition
Nonampullary duodenal adenomas are benign neoplastic polyps arising from the glandular epithelium of the duodenum that occur outside the major papilla; they have a high risk of malignant transformation.
Epidemiology
The prevalence of nonampullary duodenal adenomas is approx. 0.03–0.4%. [7]
Etiology [7]
- Hereditary polyposis syndromes, e.g.:
- Sporadic: risk factors include
- Current smoking
- Barrett esophagus
- History of other malignancy
Classification [7]
Duodenal adenomas may be classified based on location, clinical context, and/or histological phenotype.
- Location: ampullary or nonampullary
- Context: sporadic or polyposis-associated
- Histological phenotype: intestinal-type or gastric-type (e.g., gastric foveolar-type, pyloric gland adenoma)
Clinical features [7]
Most individuals are asymptomatic, and lesions are typically discovered incidentally during EGD for other indications.
Diagnosis [7]
- EGD: subtly elevated, superficial mucosal lesions with white or red color
- Biopsy: avoided when endoscopic features suggest an adenoma (provides limited diagnostic value and can compromise resection)
- Colonoscopy: to screen for concurrent colonic adenomas or colorectal carcinoma
Management [7]
- Endoscopic resection is recommended because of the high risk of malignant transformation.
- Surgical therapy is reserved for lesions not suitable for endoscopic resection and for patients with complications or confirmed malignancy.
- Surveillance endoscopy is indicated after resection; intervals are based on lesion size, histology, and completeness of resection.
Complications [7]
The primary complication of duodenal adenomas is malignant transformation.
Small intestine hemangioma
Definition [8]
Small intestine hemangiomas are benign vascular tumors originating from the submucosal vascular plexus; they most commonly affect young individuals and are typically located in the jejunum.
Epidemiology
- Prevalence: 7–10% of benign small intestine neoplasms, 0.05% of gastrointestinal tract neoplasms [8]
- Age: most commonly occur in young individuals (5–25 years of age) [8]
- Sex: ♀ > ♂ (2.5:1) [8]
Etiology [8]
Most small intestine hemangiomas occur sporadically; multiple hemangiomas may be associated with syndromes such as:
Classification [8]
There are three histological types of small intestine hemangiomas.
- Cavernous (most common): characterized by large, dilated vascular channels lined by multiple endothelial layers
- Capillary: composed of a proliferation of small, thin-walled capillaries
- Mixed-type: contains features of both cavernous and capillary types
Clinical features [8]
Most individuals with small intestine hemangiomas are symptomatic and commonly present with:
- Gastrointestinal bleeding: chronic, recurrent, and painless
- Features of anemia
Diagnosis [8]
Consider small bowel hemangiomas in patients with recurrent or unexplained gastrointestinal bleeding after nondiagnostic EGD and colonoscopy.
Imaging
- Abdominal x-rays: may show phleboliths (present in ∼ 50% of cases) [8]
- CT enterography: transmural wall thickening, phleboliths, and homogeneous contrast enhancement
-
MRI
- Low signal on T1-weighted images
- High, heterogeneous signal on T2-weighted images
Endoscopy
-
Push enteroscopy (e.g., double-balloon enteroscopy, spiral enteroscopy)
- Allows for direct visualization and potential therapeutic intervention
- Blue or red compressible submucosal nodules
- Capsule endoscopy: evaluates for occult gastrointestinal bleeding; may detect vascular lesions
Differential diagnoses [8]
Benign and malignant lesions of the small intestine, e.g.:
Management [8]
The management approach depends on the presence and severity of symptoms.
- Asymptomatic: conservative management
- Symptomatic: surgical resection of the affected intestinal segment
Complications [8][9]
Small intestine lipoma
Definition [5][6]
Small intestine lipomas are benign, sporadic subepithelial lesions composed of mature adipocytes arising from the submucosa; they can occur anywhere in the gastrointestinal tract.
Clinical features [5][6]
Most small intestine lipomas are asymptomatic; symptoms are usually caused by large lipomas and include:
- Abdominal pain
- Clinical features of gastrointestinal bleeding
- Clinical features of bowel obstruction
- Clinical features of intussusception
Diagnosis [5][6]
A definitive diagnosis is based on endoscopy and imaging findings without the need for biopsy.
Endoscopy
- Appearance: slightly yellow submucosal lesion
- Positive pillow sign: easily indents when pressed with closed biopsy forceps
- Positive tent sign: mucosa tents upward when grasped, indicating a pliable submucosal lesion
Imaging
- EUS: submucosal, hyperechoic lesion
- CT: hyperechoic lesion with Hounsfield units identical to fat
Biopsy
- Not required if endoscopic and imaging findings are typical
- Histopathologic findings (if obtained): uniform, mature adipocytes without cytological atypia
Differential diagnoses [5]
Management [5]
Management is symptom-based; routine surveillance is not indicated.
• Asymptomatic: no resection
• Symptomatic or large lesions: Resection may be considered.
Complications [6]
Complications are rare and typically only occur with large lipomas.