Histologic Correlates of Non-Calcific Chronic Pancreatitis by EUS: A Prospective Tissue Characterization Study

Aims: The significance of EUS features of non-calcific chronic pancreatitis (NCCP) remains unclear. Aim: Correlate EUS criteria for NCCP with histology from surgical specimens. Methods: Prospective study of ALL patients who underwent pancreatico-biliary EUS and subsequent pancreatic surgery over a 1-yr period. Patients with calcific CP were excluded. Using standard EUS criteria, individual CP features were carefully documented with relation to different parts of the pancreas, particularly, farther away from the pathology being evaluated. All patients underwent surgery within 2 months of EUS; none received preoperative chemo-radiation. A single pathologist blinded to EUS findings reviewed specimens and graded fibrosis (total score 12; ≥6=unequivocal CP). Quantitative ROC curve analysis and Spearman rank correlation coefficients were calculated. Results: Of 42 patients evaluated, NCCP was diagnosed by histology in 21 (50%). By ROC curve analysis, ≥4 EUS criteria provided the best sensitivity (90.5%), specificity (85.7%), and accuracy (88.1%) for diagnosing NCCP. Parenchymal EUS features significantly associated with histologic NCCP were foci (p<0.0001), stranding (p<0.001) and lobulation (p=0.04); ductal features were dilated (p<0.0001) or irregular main pancreatic duct (p<0.0001), side branches (p<0.001) and hyperechoic margins (p=0.03). There was a significant correlation between number of EUS criteria and severity of NCCP on histology (r=0.85; p<0.0001). Disease-free areas of the pancreas determined as being normal by EUS were normal at histology: Patients without CP/minimal disease by EUS (EUS criteria=0–3) had none or only minimal fibrosis at histology (score<4/12). Conclusions: This prospective study demonstrates an excellent correlation between endosonographic and histological findings of NCCP.