Histopathologic correlation of endoscopic ultrasound findings of chronic pancreatitis

Purpose: To provide histologic correlation of endoscopic ultrasound (EUS) findings believed to represent chronic pancreatitis (CP). Methods: Eleven post-mortem pancreatic specimens with histopathologic evidence of chronic pancreatitis were examined in-vitro by radial scanning EUS at 7.5 MHz in a fluid bath. This was done immediately after dissection of the pancreas from the autopsy. The pancreata were studied by EUS for the following features: (1) Echogenic foci (2) Hypoechoic foci (3) Echogenic main pancreatic duct (MPD) 4. Accentuated lobular pattern (5) Cysts (6) Irregular MPD 7. Dilated MPD 8. Side branch dilation. The present of ≥ 3 of above features was considered to be diagnostic for chronic pancreatitis. The pancreata were then sent to the pathologist (blinded to the EUS findings) for histopathologic examination. Two pathologists who were blinded to each other's findings independently assessed the pancreata for chronic pancreatitis. Prior to beginning this study, both pathologists agreed that the following features represented chronic pancreatitis: (1) Ductal changes - proliferation, dilation, blockage or plugging (2) Inflammatory changes - round cell infiltration (3) Fibrosis-periductal, interlobular and intralobular (4) Atrophic acinar changes (5) Cyst formation. Results: Three of 11 pancreata had severe autolysis and thus a complete histologic evaluation could not be performed. Seven of the other 8 pancreatitis specimens had evidence of CP by EUS (≥3 EUS features of CP). In one case (1/8) although a portion of echogenic MPD was seen in the head, a complete ultrasound evaluation could not be performed as the MPD could not be seen in the body and tail. Histopathologic examination revealed varying degrees of chronic pancreatitis in all 8 pancreatic specimens based upon the histological criteria described above. Conclusions: (1) The presence of ≥ 3 EUS features of chronic pancreatitis correlates with the histologic diagnosis of chronic pancreatitis (2) EUS is a sensitive method for the diagnosis of chronic pancreatitis (3) An endosconographic to pathologic, feature to feature correlation is underway.