Radin et al (1987) also described the ... Radin DR, Colletti PM, Ralls PW, Boswell Jr WD and Halls ... Chou C K, Max C W Lin, M B Tzeng WS and Chang J M.
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CASE
REPORT
Agenesis of Right Lobe of Liver: Role of Multislice Computed Tomography *Garg K.C.,*Venkatraman B.,**Chacko K.C. ^Department of Radiology, **Department of Medicine Hamad Medical Corporation Doha, Qatar
Abstract:
Case Report:
Congenital anomalies of the liver are rare. Agenesis of the right lobe of liver is a rare anomaly with 43 cases reported so far in the English literature. Hypoplasia and agenesis occur more on left side. Agenesis of right lobe of liver is presented in this case report. Role of multislice computed tomography is highlighted in diagnosis. A brief literature review is made along with discussions on differential diagnosis.
A 42 yrs old lady attended medical outpatient with complaints of upper abdominal fullness, vomiting and swelling of left side of abdomen of few months duration. On examination patient had unremarkable general examination. Liver was palpable in mid and left side of the abdomen. Spleen was mildly enlarged. There were no clinical suggestions of ascitis or collateral venous flow. Laboratory investigations revealed normal cholesterol, triglycerides, glucose and liver enzymes Alkaline phosphatase however was mildly elevated (76 u/1). Hepatitis-B antigen was negative. Hepatitis-B surface antibody levels were 769 miu/ml Ultrasonography of the abdomen revealed mild splenic enlargement with a focal cystic lesion at the mid part. Liver was midline in position with enlarged left lobe encroaching on to spleen. Right lobe of liver could not be defined. Gall bladder was not visualised. Examination of rest of the organs was unremarkable. In view of uncertain anatomical configuration of the liver, CT examination was recommended for defining the anatomy of liver.
Introduction: The liver is anatomically subdivided in to a large right lobe and a smaller left lobe by the attachment of falciform ligament and fissures of ligamentum teres and ligamentum venosum. Caudate lobe and a quadrate lobe are present in the right lobe which are separated by porta hepatis. During the early development the left and right umbilical veins are formed. The right umbilical vein disappears first but left umbilical vein transforms and after birth gets converted in to ligamentum teres. Developmental anomalies in the biliary tract occur mainly in the extrahepatic part and its vascular tree. The liver itself is free from major congenital anomalies. Between the two lobes agenesis and hypoplasia occur more often in left lobe(1). Diagnosis of these rare anomalies are discovered incidentally by imaging methods like ultrasonography and computed tomography. New developments in CT imaging namely multislice computed tomography has greatly facilitated the detection and precise demonstration of these lesions. We report a case of agenesis of l he right lobe with compensatory hypertrophy of the left lobe b y multislice CT examination.
Address for correspondence: Kailash C. Garg, MD, FFR Department Of Radiology, Hamad Medical Corporation p -0. Box 3050, Doha Qatar
Triphasic multislice CT examination of the abdomen and pelvis after bowel opacification revealed total absence of right lobe of liver. Gall bladder was suprahepatic in position (Figure 1). Right hepatic artery and right hepatic vein were not visualized. Left hepatic artery was normal in caliber and showed position medial to the portal vein. Superior mesenteric artery was normal in configuration, without showing replaced or accessory vessels. Distal Superior mesenteric artery was displaced to the right. Left hepatic lobe was enlarged, extending inferiorly, anterior to the transverse colon upto left lumbar region displacing the proximal loops of jejunum inferiorly. Left hepatic vein was present separating medial and lateral segments. Right adrenal was not seen. Portal vein and inferior vena cava were in apposition due to absence of caudate lobe. IVC was extrahepatic due to absence of right lobe. Hepatic flexure of the colon was extending to subphrenic position along the posterior abdominal wall (Figure 2). Third part of duodenum showed incomplete rotation due to enlarged left lobe of liver. Mild splenomegaly was demonstrated with a well defined nonenhancing 1.5 cm cystic lesion in the middle third of spleen.
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Agenesis of Right Lobe of Liver. . .
Figure 1: Axial image demonstrating suprahepatic position of gall bladder and subphrenic location of large bowel due to absence of right hepatic lobe.
Garg K.C.y et. al.
Figure 3: Coronal reconstruction at more posterior position show high postion of hepatic flexture and incidental cystic lesion in the spleen.
those material. Agenesis of right lobe of liver occurs slightly more often in men with 14 cases reported compared to 10 cases in women in the relevant study group. In approximately one third of them, diagnosis was suspected clinically in the 7th decade of life. Rest of the age range varied between 2nd to 6th decades(3). Left liver lobe is distinctively large in infant than in adults (Symington 1914). Hypoplasia and agenesis occur more often in the left lobe(4). 43 cases of agenesis of right lobe of liver have been reported before this index case.
Figure 2: Coronal reconstruction confirming absent right lobe of liver, hypertrophy of left lobe and altered positions of gall bladder and hepatic flexure of colon. Pancreas, kidneys, left adrenal and aorta were normal. Incidentally there was enlargement of left ovarian vein originating from a cluster of variceal veins in pelvis subsequently draining to left renal vein. Understanding of the complex anatomy was greatly facilitated by multiplanar imaging and 3D reconstructions (Figure 3). Hence diagnosis of agenesis of right lobe of liver with compensatory hypertrophy of left lobe was considered. Spleinc lesion was considered to be a simple congenital cyst.
Discussion: In first half dozen of reported cases of agenesis of right lobe of liver were discovered at autopsy and were reported between 1870 and 1923(2). Due to paucity of clinical information available in those cases, detailed analysis was not possible in
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Failure of the right portal vein to develop or an error in the mutual induction between the primitive diaphragm (septum transversum) and endodermal diverticulum representing primitive liver are possibly responsible for this developmental anomaly(2). Portal hypertension has been reported in association with agenesis of Right lobe but was not present in our case. The main patho-physiologic hypothesis for agenesis and portal hypertension is the arrest of hepatic development during foetal life(4). In the differential diagnosis of an absent or unusually small Right lobe of liver includes cirrhosis, cholangiocarcinoma, prior surgical resection in addition to agenesis(3). The absence of intrahepatic bile duct dilation helps to distinguish agenesis of Right lobe from atrophy due to cholangiocarcinoma. Suprahepatic location of gall bladder and hypertropthy of left lobe of liver and caudate lobe lend support to the diagnosis of agenesis of right lobe of liver(4). Our patient also had left lobe hypertrophy and suprahepatic location of gallbladder. Persistence of right umbilical vein is traditionally considered to be extremely rare, sometimes associated with agenesis of right hepatic lobe(1). Earlier these anomalies were discovered during laparotomy, autopsy or dissection. But recently they have been noticed frequently during routine ultrasound, computed tomographic examinations and angiography(1). Imaging findings described included the absence of right hepatic lobe, varying degree of enlargement of left lobe and caudate lobe of liver,
QATAR MEDICAL JOURNAL | VOL. 16 / NO. 1 / JUNE 2007
Garg K.C., et. al.
Agenesis of Right Lobe of Liver.
presence of retro and supra hepatic gallbladder and a persistent right umbilical vein(1'3'5). Radin et al (1987) also described the alteration in the hepatic lobar morphological characters and association of portal hypertension, cholelithiasis in association with right lobe agenesis. Imaging of liver anomalies has become more exacting with the advent of multislice computed tomographic imaging, which can individually visualize vascular anatomy, parenchymal
changes and surrounding relations. Coronal and saggital reconstructions particularly demonstrate, in addition to morphology, relation with diaphragm, subphrenic location of gallbladder and extrahepatic location of the inferior vena cava as shown in our case. MRI definitely has an equally important role in demonstrating these anomalies. However it falls short in showing altered location of the bowel loops, which are part of the observation in lobar hepatic agenesis.
References: 1. N. Shankar and S. Rabi, A rare case of combined hypoplasia of right lobe of liver and persistent right umbilical vein (2005), EurJAnat, 9(1)55-57. 2. Bertrand L, Jabon M. Une cause inedited d'hypertention portale: I'agenesie du lobe drot dufoie. Rev Int Hepatol 1962: 12; 897-920. 3. Radin DR, Colletti PM, Ralls PW, Boswell Jr WD and Halls
JM(1987) Agenesis of right lobe of liver, Radiology, 164: 639-642. 4. Gathwala G and Sen J (2003) Agenesis of right lobe of liver. Indian J Pediatrics, 70: 183-184. 5. Chou C K, Max C W Lin, M B Tzeng WS and Chang J M (1998). CT of agenesis and atrophy of right hepatic lobe. Abdominal Imaging, 23: 603-607.
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