Epithelial hyperplasia of the gallbladder in children with anomalous pancreaticobiliary ductal union.

Objective: Few data are available on the fate and incidence of epithelial hyperplasia throughout the life of anomalous pancreaticobiliary ductal union (APBD) patients. The pathological study in pediatric APBD patients is less recognized.

Methods: Ten resected gallbladders obtained from children with APBD and control patients without APBD were examined histologically, and immunohistochemically for the detection of Ki-67 (as a proliferative marker) and p53. K-ras mutations in codon 12 were also examined. Epithelial hyperplasia was classified into high-grade and low-grade hyperplasia.

Results: Six (60%) of 10 patients with APBD had epithelial hyperplasia of the gallbladder, whereas no patients without APBD exhibited this lesion. Diffuse epithelial hyperplasia was observed in 1 (50%) of 2 undilated-type APBD and 5 (63%) of 8 dilated-type. Two (33%) of 6 patients with epithelial hyperplasia exhibited high-grade hyperplasia. Ki-67 labeling index (LI) was significantly higher in hyperplastic mucosa than in control gallbladder mucosa. K-ras mutations and p53 overexpression were not detected in hyperplastic and normal mucosa.

Conclusions: Epithelial hyperplasia of the gallbladder accompanied by increased proliferative activity exists at birth or is acquired in childhood with APBD patients and may be an important factor predisposing to the development of gallbladder carcinoma.