centroacinar

Centroacinar refers to the region and cells at the center of the pancreatic acinus, specifically the centroacinar cells that line the initial portion of the intralobular duct system. The term is used to describe the arrangement within the exocrine pancreas where acinar cells produce digestive enzymes that are drained into ducts beginning with intercalated or centroacinar ducts.

Anatomical and histological context: In the pancreatic lobule, each acinus consists of secretory acinar cells surrounding a small ductal passage. At the distal end of the acinus, centroacinar cells form the lining of the centroacinar duct, transitioning between acinar tissue and the ductal network. These cells are typically flatter or cuboidal with relatively scant cytoplasm and a basally located nucleus, and they lack the dense zymogen granules seen in acinar cells. The centroacinar ducts give rise to intralobular ducts as secretions move toward the collecting duct system.

Function: The exact role of centroacinar cells is not fully settled. They are part of the ductal architecture and are thought to contribute to the modification of the pancreatic juice, including ionic composition and bicarbonate content, as fluid passes from the acini into the ductal tree. Their presence marks the boundary between enzyme-secreting acini and the ductal system.

Clinical relevance: Pathologically, the term appears in descriptions of pancreatic histology and in rare tumor contexts, such as centroacinar cell carcinoma, a very uncommon pancreatic neoplasm arising from these cells. Understanding centroacinar anatomy helps distinguish acinar, ductal, and centroacinar components in pancreatic diseases.