Clinical/pathological analysis of gallbladder adenomyomatosis; type and pathogenesis

The aim of this study was to analyze the clinical/pathological outcomes of patients that underwent surgery for gallbladder adenomyomatosis, to clarify the characteristics of the type and pathogenesis of adenomyomatosis.

From May 1997 to March 2008, 4704 consecutive patients underwent cholecystectomy at Ajou University Medical Center. Among them, 113 (2.4%) patients that were histopathologically diagnosed with adenomyomatosis or adenomatous hyperplasia were selected for this study. The patients were divided into a fundal type group and a segmental/diffuse type group, and the specimens reviewed with Hematoxylin-Eosin (H & E) and immunohistochemical stainings.

Sixty-three patients were male and 50 female; the age ranged from 17 to 76 years of age. The fundal type was the most common type. Gallstones were present in 69.9% of the patients. In the analysis of the fundal and segmental/diffuse types, gallstones were present in 23 patients with fundal type and in 53 patients with segmental/diffuse type; this difference was statistically significant (p < 0.05). Review of H & E staining showed that the most common findings were grade 1 (n = 14) in the fundal type and grade 2 (n = 23) in the segmental/diffuse type; there was a significant difference in the inflammatory grade (p < 0.05). Immunohistochemical staining showed expression of vimentin, as a mesenchymal marker in 28.0% of cases (n = 16).

The fundal type differed from the segmental/diffuse type based on the clinical/ pathological features; it had a lower frequency of gallstones and a lower inflammatory grade. In addition, no cancer was identified in the resected gallbladders of patients with adenomyomatosis. The findings suggest that the Rokitansky-Aschoff sinuses (RAS) were associated with acquired motility, based on the expression of vimentin, consistent with an epithelial-mesenchymal transition.