The histopathology of fundic gland polyps of the stomach.

To assess the histopathologic features of fundic gland polyps (FGP) of the stomach, 83 specimens from 25 patients were examined. In nine patients, FGP were associated with an inherited adenomatous polyposis syndrome; the other 16 patients had nonsyndromic FGP. FGP were microscopically characterized by the presence of fundic glands with variably disordered architecture, a feature not previously emphasized. Disordered architecture, found in 80 of 83 specimens (96%), comprised a spectrum of abnormalities, ranging from prominent glandular and cellular budding, found in 51 biopsies (61%), to irregular tortuous glands, noted in 61 biopsies (75%), to microcysts lined by fundic epithelium, seen in 72 biopsies (87%). The continuous range of these changes suggested that FGP arise through progressive formation and unfolding of secondary glandular buds, to result in cystic dilatation. No differences were found between syndromic and nonsyndromic FGP with respect to histologic features or mucin histochemistry, including presence of O-acylated sialomucins.