PATHOMORPHOLOGICAL FEATURES OF THE PANCREAS DEPENDING ON CHRONIC PANCREATITIS DURATION

Introduction. Chronic pancreatitis (СР) presents clinically as an inflammatory process that leads to complex morphological changes, resulting in the replacement of pancreatic parenchyma with connective tissue and the development of various complications. Defining an optimal surgical strategy remains a relevant issue today. The purpose of the study was to assess the morphological and immunohistochemical characteristics of the pancreatic parenchyma depending on СР duration. Methods. A total of 147 (57.1%) patients were examined retrospectively. A prospective comparative study involving 257 patients analyzed the short and long-term outcomes to evaluate the effectiveness of the “early surgery” strategy developed at the clinic and the surgical management methods for СР. The study conducted a morphological and immunohistochemical assessment of the pancreatic parenchyma, analyzing the long-term outcomes of the primary pathogenetic surgical treatments for СР. Results. Morpho-functional changes in the pancreatic parenchyma, observed more than three years (median 5.85 years) after the onset of CP clinical manifestations, were characterized by progressive fibrosis due to increased expression of type I collagen and fibronectin, which resulted in dense cuff-like perineural and perivascular fibrosis and stenosis of the pancreatic ducts around tubular complexes, clinically corresponding to the presence of intense pain syndrome. Conclusions. An essential role of pancreatic stellate cells in developing pancreatic parenchymal fibrosis in CP has been established. Fibrotic lesions of the pancreas are irreversible, and the resulting morphological and structural changes lead to both exocrine and endocrine dysfunction. More than three years after the onset of clinical manifestations of CP, type I collagen expression was observed in the acinar tissue, with thin strands detected within the islets of Langerhans. Intraepithelial ductal neoplasia was also identified, which may later progress to ductal adenocarcinoma of the pancreas. It has been demonstrated that the improvement in surgical outcomes for complicated forms of CP with biliary and ductal hypertension is achieved through planned surgery within the first three years of CP development, before the onset of irreversible pathological changes, including the potential for oncological transformation of the pancreas.