Gastric pyloric gland adenoma: a multicentre clinicopathological study of 67 cases

Aims There is limited information regarding the clinicopathological and immunohistochemical characteristics of gastric pyloric gland adenomas ( PGA s). Methods and results Sixty‐seven cases of gastric PGA from 57 patients were analysed. PGA s occurred with similar frequency in men and women (47.4 and 52.6%, respectively), with a mean age of 66 years. Most presented in the gastric body/fundus (67.2%). Fifteen cases (22.4%) developed against a background of autoimmune gastritis ( AIG ), whereas normal mucosa was seen in 35.8%. Only 16.4% (11 cases) developed in patients with a genetic predisposition, most commonly familial adenomatous polyposis. Low‐grade lesions had a mean size of 1.5 cm, while PGA s with high‐grade dysplasia ( HGD ) or adenocarcinoma had a mean size of 3.5 cm ( P < 0.001) and more commonly showed tubulovillous architecture (50.0 versus 25.6% in low‐grade dysplasia; P = 0.040). Most PGA s (61.2%) co‐expressed mucin ( MUC )5 AC and MUC 6 (mixed type), which was associated significantly with HGD or adenocarcinoma ( P = 0.013). AIG was also associated with HGD ( P = 0.027), but genetic predisposition did not correlate with the grade of dysplasia ( P = 0.793). The recurrence rate of PGA was similar for high‐ (11.8%) and low‐grade lesions (7.4%) ( P = 0.624). Conclusions The risk of HGD increases with the size of PGA , tubulovillous architecture and the presence of AIG as well as mixed immunophenotype. As the overall local recurrence rate is less than 10%, PGA s may be treated conservatively, but they should be excised completely if possible, particularly if they are large or show high‐grade features.