Gastric Polyps

 Hyperplastic, adenomatous, and hamartomatous



• Fundic gland polyps: Now most common type
image Associated with use of proton pump inhibitor (PPI) medication

image Sometimes considered a variant of hyperplastic polyps

• Hyperplastic polyps
image Virtually no malignant potential

image Typical: Small, multiple, sessile (< 1 cm)

image Location: Fundus and body

• Adenomatous polyps
image Less common (< 20% of benign polyps)

image Increased risk of malignant change

image Usually solitary, > 1 cm

• Hamartomatous polyps
image Peutz-Jeghers syndrome

image Can occur as isolated finding (sporadic)




TOP DIFFERENTIAL DIAGNOSES




• Retained food and pills

• Gastric carcinoma (polypoid type)

• Gastric metastases and lymphoma

• Gastric gastrointestinal stromal tumor

• Ectopic pancreatic tissue


CLINICAL ISSUES




• Prevalence of gastric polyps in patients who have upper endoscopy = 6% (2009 study)

• Fundic (77%), hyperplastic (17%), malignant (2%), adenomas (< 1%)

• Much higher percentage of fundic polyps than in earlier studies
image Caused by increased use of PPI medications

• Syndromic polyps have high association with cancer risk in stomach and other organs
image e.g., familial polyposis, Peutz-Jeghers syndrome

image
(Left) Graphic shows a pedunculated polyp in the gastric antrum, prone to prolapse through the pylorus with peristalsis. Any type of large polyp may prolapse in this fashion, including large hyperplastic, adenomatous, and even polypoid masses arising from the submucosa, such as lipomas.


image
(Right) Upper GI series shows a polypoid mass image in the duodenal bulb that is a prolapsed gastric antral polyp (adenoma).

image
(Left) Film from an upper GI series in a 57-year-old man shows multiple small, sessile polyps image in the gastric body. The appearance and age of the patient are typical for hyperplastic polyps.


image
(Right) Film from an upper GI series of adenomatous polyps in a patient with familial polyposis shows innumerable small polyps throughout the stomach. These are somewhat larger, more numerous, and more irregular in shape than most hyperplastic polyps.


TERMINOLOGY


Definitions




• Protruding, space-occupying lesion within stomach
image Encompass a broad spectrum of conditions that may originate in gastric mucosa or submucosa


IMAGING


General Features




• Best diagnostic clue
image Radiolucent filling defect, ring shadow, or contour defect on barium study

• Morphology
image Hyperplastic polyps: Smooth, sessile
– Fundic gland polyps: Always sessile, multiple, small

image Adenomatous polyps: Usually single with lobulated or cauliflower-like surface

image Hamartomas: Cluster of broad-based polyps

• Other general features
image Polyps classified  based on pathology

image Fundic gland polyps
– Variant of hyperplastic polyps (< 1 cm)

– Have become most common type of gastric polyp

– Associated with use of proton-pump inhibitor medication

image Hyperplastic polyps
– Virtually no malignant potential

– Typical: Small, multiple, sessile (< 1 cm)
image Location: Fundus and body

– Atypical large: Solitary, pedunculated (2-6 cm), location in body and antrum

– Atypical giant: Polyp (6-10 cm) multilobulated mass, location in body and antrum

image Adenomatous polyps
– Less common (< 20% of benign polyps); dysplastic lesions

– Increased risk of malignant change via adenoma-carcinoma sequence

– Usually solitary, occasionally multiple, > 1 cm
image Location: Mostly antrum > body

– Histologically: Tubular (75%), tubulovillous (15%), villous (10%)

– Gastric adenomatous polyps 30x less common than gastric cancer

– Carcinoma in situ and invasive carcinoma: Seen in 50% of adenomatous polyps > 2 cm

– 30-40% associated with atrophic gastritis, pernicious anemia, and cancer

– Higher risk of coexisting gastric cancer than risk of malignant change in polyp

image Polyposis syndromes involving stomach
– Familial adenomatous polyposis (FAP) syndrome 
image > 50% of patients have gastric adenomatous or fundic gland polyps

– Hamartomatous polyposis (e.g., Peutz-Jeghers syndrome [PJS])
image Have increased risk of gastric and other cancers

– Cronkhite-Canada, Cowden, etc.
image All rare but associated with gastric polyps

Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Gastric Polyps

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