A Radiological Review of the Varied Duodenal Lesions with Histopathological Correlation

Review Article

Austin J Radiol. 2023; 10(3): 1219.

A Radiological Review of the Varied Duodenal Lesions with Histopathological Correlation

Ramachandran R¹; Dhamodaran J¹*; Paneerselvam P¹; Balasubramanian S²; Rangasami R¹

¹Centre of Excellence in Radiology and Imaging Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai, India

²Department of Pathology, Sri Ramachandra Institute of Higher Education and Research, Chennai, India

*Corresponding author: Jeevitha Dhamodaran Centre of Excellence in Radiology and Imaging Sciences, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, India. Tel: 7094472904 Email: djeevithaa15@gmail.com

Received: July 03, 2023 Accepted: August 07, 2023 Published: August 14, 2023

Introduction

Majority of the duodenal lesions have received little attention in imaging literature in comparison with jejunum and ileum as most of them are primarily investigated with conventional endoscopy. Cross sectional imaging techniques–Multi Detector Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) have dramatic improvement in diagnostic capabilities as they can analyse the wall of the duodenum, intraluminal content, submucosal extent of the disease, and infiltration into the surrounding viscera. Few of the duodenal lesions have overlapping imaging characteristics and it is crucial to correlate these conditions with histopathological analysis for definitive diagnosis. The main aim of this imaging review is to elucidate the diverse spectrum of duodenal lesions with emphasis on CT and MRI imaging features.

Anatomy

The duodenum is the first part of the small bowel and has a complex anatomicalposition and important visceral relationships which poses a challenge. The normal duodenum measures approximately 25 cm in length and 2.5 cm in transverse diameter, with mucosal folds measuring roughly 2 mm in thickness. Traditionally, the duodenum is divided into four segments [1]. The first portion, commonly known as the duodenal bulb, is intraperitoneal and extends from the gastric pylorus to the level of gallbladder neck. The second portion includes an upper and lower flexure, extends retroperitoneally from the gallbladder neck to the level of the lumbar spine. The third portion extends retroperitoneally from right to left and traverses anterior to inferior vena cava and aorta. The fourth portion ascends to the ligament of Treitz [4]. The serosa surface of the descending duodenum is closely related to the pancreatic head, forming the pancreaticoduodenal groove, an anatomic space that contains pancreaticoduodenal arterial arcades, mesenteric veins, and lymphatics. Both bile and pancreatic fluids drain into the duodenum, via ductal insertions which could have varied anatomical location.

Congenital Anamolies

Duodenal Diverticulum

The duodenum arises from the embryonic midgut and is composed of both endodermal and mesodermal tissue. Due to abnormalities in recanalization, true duodenal diverticula and duplication cyst arises [2]. The most common location of the duodenal pseudo diverticula is along the medial wall of 2nd and 3rd part of duodenum [3]. When these pseudo diverticula compress the intrapancreatic portion of common bile duct causing obstructive jaundice, it is called as lemmel syndrome [4]. These patients may sometimes present with duodenal diverticulitis, which can be complicated by perforation into the retroperitoneal space portion. On CT, diverticula appear as focal out pouching from second and third part of duodenum filled with either air, fluid or both air & fluid [3].

Duplication Cyst

Duplication cysts can occur anywhere in the alimentary tract. Approximately 12% involve the gastroduodenal region, usually along the medial aspect of the D2 or D3 segment of the duodenum [2]. They are usually asymptomatic and are often incidentally detected, but symptoms related to obstruction or secondary infection can occur. The pathognomonic imaging finding of on ultrasound includes “gut signature sign”- that shows a classical five - layered cyst [5,6]. CT shows a non-enhancing low-attenuation cystic mass with a peripheral enhancing rim. On MRCP, we could appreciate a well circumscribed T2 hyperintense lesion with a hypointense wall that shows no obvious communication with the duodenum [7].

Annular Pancreas

It is a rare congenital anomaly in which the normal pancreatic tissue encircles the second portion of duodenum either completely or incompletely. Embryologically, the pancreas develops from the dorsal (single) and ventral (bifid) pancreatic buds of primitive foregut. During normal development, one of the ventral bud (left) atrophies and the right ventral bud rotates to fuse with the dorsal bud. Persistence of the bifid ventral bud or malrotation of a portion of the right ventral bud encircles the 2nd part of duodenum resulting in annular obstruction [8]. It presents normally during childhood with features of gastrointestinal or biliary obstruction and are mostly associated with other congenital anomalies (Tracheoesophageal fistula, imperforate anus or Hirsprung disease) [9]. However, it can present in adulthood as peptic ulcer disease or pancreatitis [9]. Annular pancreas may be detected on CT as a ring of pancreatic tissue encasing the descending or 2nd part of duodenum either completely or incompletely (Figure 3.1).