A Rare Annular Pancreatic Anomaly

ABSTRACT

During routine abdominal dissection of an adult male cadaver aged about 60 years, an anatomical variation was found in the pancreaticoduodenal area. The dissection was performed in the Department of Anatomy, JSS Medical College, Mysuru. It was observed that the pancreatic tissue completely encircled second part of duodenum. It consisted of a 360-degree pancreatic ring, it measured around 2 cm in width on its lateral aspect and 5 cm width on its posterior aspect. It measured 4 cm width on its anterior aspect. The part of the duodenum, which lies proximal and distal to the annular pancreas was found distended. A piece of annular pancreas was collected, later was subjected to the histopathological examination under H & E stain. The microscopic structure showed the normal architecture of the pancreatic tissue. Understanding the pancreas development is essential to understand its congenital defects. It develops from ventral and dorsal pancreatic buds; it lies near the developing primitive duodenum. Due to the axial rotation of the second part of the duodenum, the ventral pancreatic bud winds around the posterior surface of the duodenum to meet with the dorsal pancreatic bud. This normal event may tend to show some derangement leading to variable conditions of pancreatic anomalies like the annular pancreas, pancreas divisum, pancreatic duct defects, etc. Though the congenital pancreatic anomalies are relatively uncommon, they may remain asymptomatic for a long duration, often they may find incidentally in some investigations or during surgeries. During our routine dissections, we have come across one such anomaly of the annular pancreas. Meeting such anomalies or variations during gross anatomy dissections will certainly create an overwhelming interest among the students to understand and correlate its embryological basis, and its clinical implications. Annular pancreas (AP) was first described by Tiedemann (1818), the name “Annular Pancreas” coined by Ecker (1862). It is a rare congenital anomaly formed by a thin band of normal pancreatic tissue that completely or partially encircles the second part of duodenum. The reported incidence in adults varies from 0.005 to 0.015 %.1