Atrophy of anterior and medial segments commonly follows development of focal confluent fibrosis in cirrhosis
Look for signs of portal hypertension (varices, ascites, etc.)
• Postsurgical resection
For hepatic resection, incisions can be made along longitudinal or transverse scissurae or both combined
• Post chemoembolization or ablation
Hyperattenuation of atrophic liver parenchyma
Check prior imaging studies and medical records for evidence of prior tumor and treatment
CLINICAL ISSUES
• Usually asymptomatic
DIAGNOSTIC CHECKLIST
• Conditions including cirrhosis, atrophy secondary to biliary obstruction, hepatic surgery, and trauma can mimic agenesis and should be ruled out 1st
(Left) Axial CECT shows a very small medial segment lying between the falciform ligament cleft and the gallbladder . The anterior segments are also small.
(Right) Axial CECT in the same case shows the colon and omental fat filling the gap between the right and left hepatic lobes in the same patient with congenital hypoplasia of the anterior and medial segments.
(Left) Axial CECT shows hypoplasia of the anterior and medial segments. Note a clip from a prior cholecystectomy; the gallbladder normally lies in the interlobar plane. Also note the lateral and cephalic herniation of the stomach and colon .
(Right) Axial NECT of a more caudal section in the same patient shows the large gap created by congenital hypoplasia of the anterior and medial segments. The gap is filled with omental fat and the hepatic flexure of the colon .
TERMINOLOGY
Synonyms
• Agenesis or hypoplasia of hepatic lobes or segments
Definitions
• Lobar agenesis or hypoplasia is an uncommon developmental anomaly with absence of liver tissue usually to right or left of gallbladder fossa without prior surgery or disease
IMAGING
General Features
• Best diagnostic clue
Absence of right or left hepatic vein, portal vein and its branches, and intrahepatic ducts
– If none of these structures are visible, agenesis is substantiated
• Location
Most common segments involved
– Right lobe: Segments 5 and 8 (anterior segments)
Only gold members can continue reading. Log In or Register to continue
and the gallbladder 
. The anterior segments are also small.
and omental fat filling the gap between the right and left hepatic lobes in the same patient with congenital hypoplasia of the anterior and medial segments.
from a prior cholecystectomy; the gallbladder normally lies in the interlobar plane. Also note the lateral and cephalic herniation of the stomach 
and colon 
.
.
Most common segments involved
