Significance of histopathological evaluation of pancreatic fibrosis to predict postoperative course after pancreatic surgery.

Pancreatic stellate cells (PSC) play a critical role in pancreatic fibrosis and the apparent diffusion coefficient (ADC) value based on the diffusion-weighted image (DWI) from magnetic resonance imaging (MRI) may be a predictor of tissue fibrosis. This study aimed to evaluate the pancreas texture from both histopathological and radiological viewpoints and to investigate the effect of pancreas texture on occurrence of postoperative pancreatic fistula (PF). We divided 40 patients into soft-pancreas group and hard-pancreas group, according to the histopathological evaluation of pancreatic fibrosis. We compared ADC values and occurrences of PF between the two groups. Histopathological measurement lengths of interlobular and intralobular fibrosis increased significantly with the progression of fibrosis grade and PSC stage, while PSC stage correlated significantly with fibrosis grade (r=0.868, p<0.001). PF was detected in 14 out of 40 patients, including grade A in 7 patients and grade B/C in 7 patients, but there were no operative deaths. Pancreas texture (soft/hard), determined based on the combination of fibrosis grade and PSC stage, was 16/10 (no PF) and 14/0 (grade A/B/C PF) and the difference in the incidence was significant (p=0.022). Though ADC value was significantly lower in the hard-compared to the soft-pancreas group (1.48±0.42 vs. 1.73±0.27×10(-3) mm(2)/sec; p=0.033), there was no significant difference in ADC value between no PF versus grade A/B/C PF group. Histopathological evaluation of pancreas texture correlated negatively with ADC values and is critical to predict the occurrence of PF.