Aims: Gastric mucin expression has been demonstrated in a group of endocervical glandular lesions. The aim of this study was to gain further insight into endocervical lesions with a gastric phenotype.
Methods and results: Various types of tunnel clusters (TC) were examined for gastric mucin by alcian blue/periodic acid-Schiff staining and immunohistochemistry for HIK1083. Five of 34 cases of TC expressed gastric mucin defined by PAS dominant neutral mucin and immunopositivity for pyloric gland mucin. Histologically, TC expressing gastric mucin showed lobular arrangements of small to medium-sized glands composed of mucin-rich columnar cells and were classified as Flumann's type A TC. Neither type B TC nor normal endocervical glands expressed PAS dominant neutral mucin and none of them was immunopositive for pyloric gland mucin. Five patients with type A TC of gastric phenotype ranged in age from 33 to 79 years (mean 58 years) and were multiparous. Type A TC of gastric phenotype, ranging from 2 to 4 mm in maximum diameter, were incidental findings in hysterectomy specimens.
Conclusion: Type A TC of gastric phenotype could be related to lobular endocervical glandular hyperplasia of gastric phenotype. The pathogenesis of gastric metaplasia in TC remains unclear.