Complete Agenesis of the Dorsal Pancreas

Anomalies of pancreas are occasionally reported. The mechanism and etiology are unknown. The relatively complicated embryogenesis of this organ- with its two ventral buds and dorsal bud rotation of the right ventral bud around the duodenum and eventually fusion with the dorsal analage, all takes place with a very low frequency of anatomic variation. Complete agenesis of pancreas are extremely rare, in which there is a regression of dorsal pancreatic duct of endodermal cells which normally arises from posterior duodenal wall to form upper portion of pancreas. This dorsal bud usually provides upper part of the head, the isthmus, body, tail of the pancreas and drains through santorini duct and minor papilla. The ventral bud forms the major part of the head and uncinate process. In patients with complete agenesis of the dorsal pancreas, neck, body, tail of the pancreas, accessory pancreatic duct (duct of Santorini), and the minor duodenal papilla are absent. While in partal agenesis, there is a remnant of the duct of santorini, and the minor duodenal papilla.US is the first modality for abdominal pain. But pancreas is sometimes not adequately visualized due to excessive bowel gas disturbances. While CT is valuable in depicting the pathology but information regarding the pancreatic duct anatomy on these images are difficult. MRI including MRCP is rapid and non invasive method of evaluation not only the pancreatic ductal system but also the parenchymal abnormality. It is important to recognize this anomaly because it can stimulate pseudotumoral enlargement of pancreatic head which has been noted in other congenital pancreatic anomalies such as annular and divisum pancreas. ERCP was once thought to be the gold standard in evaluating biliary tree due its superior resolution. However this technique is invasive not devoid of morbidity risk, operator dependent and also it requires catheterization of the minor duodenal papilla. But current improved MRCP using single shot rapid acquisition with relaxation is superior for conspicuity of the pancreatic duct. In summary with current noninvasive imaging modalities, we anticipate more cases will come into view. Hence better understanding of such rare congenital anomaly will be achieved.