Gastric Hamartomatous Polyps-Review and Update

Abstract

Gastric polyps are frequently encountered on endoscopic examinations. While many of these represent true epithelial lesions, some of the polyps may result from underlying stromal or lymphoid proliferations or even heterotopic tissue. Histologic examination is essential for accurate typing of the polyps to predict malignant potential and underlying possible genetic abnormalities. The focus of this review is on gastric hamartomatous polyps, which are relatively rare and diagnostically challenging. Though most of the gastric hamartomatous polyps are benign, certain types are associated with increased malignant potential. These include certain polyps associated with specific genetic familial polyposis syndromes and gastric inverted hamartomatous polyps. Identification of these polyps can result in the prevention or early diagnosis of gastric carcinoma and also help in the identification of family members with polyposis syndromes. The aim of this review is to categorize gastric hamartomatous polyps and aid in the identification of high-risk categories.

Keywords: hamartomatous polyp; polyposis; stomach.

Figure 1

(A) Gastric polyp (4 cm) (arrow) in a 24-year-old man with PJS (STK11 mutation detected). (B) Gastric polyp in PJS (STK11 mutation detected) showing fine branching smooth muscle bands (arrows) between hyperplastic gastric glands. The classic arborizing histology pattern, seen in the intestinal PJS polyps, is often not seen in stomach polyps. (C) Gastric polyps (arrow) in a 25-year-old man with JPS (SMAD4 mutation detected). (D) Gastric polyp in JPS (SMAD4 mutation detected) showing multiple cystic dilated glands (long arrow) in an edematous, inflamed lamina propria (short arrow). (E) Multiple polyps (arrow) in a 36-year-old man with CS (PTEN mutation detected). (F) Gastric polyp in CS (PTEN mutation detected) showing hyperplastic foveolar epithelium (short arrow)-lined polyp with gastric glands embedded in a heterogeneous stroma, consisting of intercalating bands of smooth muscle (long arrow), lymphoid tissue (double arrow), and variable chronic inflammatory infiltrate. (G) Gastric polyp in CCS showing hyperplastic foveolar epithelium (long arrow)-lined polyp with an edematous, inflamed lamina propria (short arrow) mimicking gastric JPS polyps or hyperplastic polyps. (H) FGPs showing dilated glands lined by parietal cells (long arrow) or mucous cells (short arrow).