-Gastric epithelial polyps (first part).Rev Gastroenterol Peru. 2003 ;23(4):277-92.
-Gastric epithelial polyps (part two).Rev Gastroenterol Peru. 2004;24(1):50-74. 

-Carcinoid -Lymphoma-Stromal tumour

Non-neoplastic  lesion presenting as as a gastric polyp - Inflammatory fibroid polyp.

Inflammatory fibroid polyps:    Path Case49

Site:  Antrum

Gross: Well circumscribed small sessile or peduculated lesion.
Microscopy :   

Blood vessels surrounded by spindle cells(CD34 positive) and chronic  inflammatory cells (mainly eosinophils). Multinucleated giant cells may be  present.
D/D: Eosinophilic gastritis (diffusely thickened ,deformed antrum, eosinophils in peripheral blood).
Eosinophilic granuloma (parasitic infection).

 Visit: Inflammatory Fibroid Polyp of the Esophagus:

Abstracts:  -Inflammatory fibroid polyp of the stomach: a special reference to an immunohistochemical profile of 42 cases. Am J Surg Pathol.1993 ; 17: 1159-1168

-CD34 expression by inflammatory fibroid polyps of the stomach. Mod Pathol 1997; 10:451-456

Site: At the site of gastroenterostomy stoma.
Gross: Multiple sessile polyp around the stoma.
Microscopy:

Resemble hyperplastic polyp.Cystically dilated glands extend through the muscularis mucosae into the submucosa. Intestinal metaplasia may be present. No evidence of any atypia.
May be associated with development of gastric stump carcinoma.

Abstracts:  -Gastritis cystica polyposa: report of 7 cases and literature review.Tunis Med. 2005 Sep;83(9):562-7.

-Pathologic features and mucin histochemistry of primary gastric stump carcinoma associated with gastritis cystica polyposa: a study of six cases. Am J Surg Pathol.1985; 9(6): 401-410

Fundic gland polyps:   

Common in patients treated with proton pump inhibitors. May also occur in patients with  familial adenomatous polyposis.
These are not premalignant lesions.
Site:  Body and fundus.
Gross:  Multiple transparent, sessile polyps usually less than 1cm in diameter.
Microscopy:   

Cystically dilated glands lined by gastric body type mucosa.
Irregular shortened foveolae, smooth muscle fibres around the dilated glands. Hypertrophy and hyperplasia of parietal cells in patients treated with proton pump inhibitors.

Abstracts:  -Chief cell hyperplasia with structural and nuclear atypia: a variant of fundic gland polyp.Pathol Res Pract. 2005;200(11-12):817-21.

-Gastric fundic polyps: a morphology study using mucin histochemistry, stereometry and MIB1 histochemistry using. Hum Pathol 1996 ;27: 896-903           

-Sporadic fundic gland polyps: an immunohistochemical study of their antigenic profile.Pathol Res Pract. 1996 Aug;192(8):808-15.

-The histopathology of fundic gland polyps of the stomach.  Am J Clin Pathol.1986 ;86(4): 498-503.

Most common type of gastric polyp. (Type I and II).
Polyp formation related to:
-Helicobacter - associated  gastritis.
-Pernicious anaemia
-Adjacent to ulcers and erosions.
-Gastroenterostomy stoma.
Gross:   Sessile or pedunculated.
Less than 2 cm in diameter.
Type I : Solitary . In the antrum.
Type II : Multiple. In distal fundic mucosa (junction of body and antrum). Central dimple noted in some cases.
Microscopy:

Elongated, tortuous glands,irregular branching. Glands lined by hyperplastic foveolar-type epithelium. Cystic changes may be present.

Other features:  -Smooth muscle fibres present in lamina propria. ;  -Stroma edematous and inflamed. ;  -Pseudo-invasion may be present.

In Type II hyperplastic  polyp, superficial glands show  onion-skin like arrangement.

Abstracts: Why is the hyperplastic polyp a marker for the precancerous condition of the gastric mucosa? Virchows Arch. 2006 Jan;448(1):80-4. Epub 2005

Cardiac glands hyperplastic polyp of the stomach.J Gastroenterol Hepatol. 2005 Sep;20(9):1461-3.

A case of gastric hyperplastic polyp with malignant transformation. Hepatogastroenterology.  2005 Jan-Feb;52(61):319-21.

Rare in stomach.

Peutz Jeghers polyp: Hyperplastic glands lined by foveolar epithelium. Broad bands of smooth  muscle fibres branch out. Path Case48

Juvenile polyp:  Antrum. May be associated with juvenile polyposis. Histologically, the glands are tortuous, elongated, and cystically dilated . Backround mucosa is  edematous and inflamed. Path Case 47

Polyps in Cronkhite Canada syndrome: (associated  with nail atrophy, alopecia or hyperpigmentation)

Polyps in Cowden's disease: Elongated cystically dilated glands with papillary infoldings. Connective tissue component - neural or muscular.

May occur as a mass in the pylorus or antrum. Central depression noted on the mucosal surface.
Histologically normal pancreatic acini and ducts are noted.

Abstract: -Pancreatic (acinar)  metaplasia of the gastric mucosa. Histology, ultrastructure, immunocytochemistry, and clinicopathologic correlations of 101 cases. Am J Surg Pathol. 1993;17:1134-1143.