Case Study

Riedel’s Lobe

Riedel’s Lobe is a normal anatomical variant characterized by a tongue-like inferior projection of the right hepatic lobe, most commonly extending from segments V and VI. It may mimic hepatomegaly or an abdominal mass on clinical examination but represents a benign morphological variation without pathological significance.

Whole Abdomen & Pelvis Sonography

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Technique: Examination performed using a convex 3.5–5 MHz transducer. Longitudinal and transverse planes of the abdomen were evaluated. Color Doppler assessment of hepatic and portal vessels was performed. Pelvic and post-void images were obtained. Patient was fasting for 6–8 hours.
Prior studies: No prior imaging available.
Clinical history: Routine sonographic evaluation.

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Liver: Liver is normal in echotexture with a prominent tongue-like inferior projection of the right hepatic lobe consistent with Riedel's lobe (normal anatomical variant). No focal lesion such as mass, cyst, or abscess is seen. Intrahepatic biliary radicles are not dilated. Portal vein is normal in caliber with normal hepatopetal flow.
Gall Bladder: Gall bladder is normal in size, shape, and echotexture. No calculus, mass, or sludge is seen. Wall thickness is normal.
Common Bile Duct (CBD): CBD is normal in course and caliber throughout its visualized length. Pancreas: Pancreas is normal in size, shape, and echotexture. Main pancreatic duct is not dilated. No focal mass or calcification is seen.

Spleen: Spleen is normal in size, shape, and echotexture. Splenic vein appears normal. No focal lesion or calcification is seen.
Right Kidney: Right kidney is normal in size, shape, and echotexture. Corticomedullary differentiation is preserved. Pelvicalyceal system is not dilated. No calculus, hydronephrosis, or mass lesion is seen.
Left Kidney: Left kidney is normal in size, shape, and echotexture. Corticomedullary differentiation is preserved. Pelvicalyceal system is not dilated. No calculus, hydronephrosis, or mass lesion is seen.
Rt. Ureter: Right ureter is visualized in its proximal segment. No evidence of dilatation. No intraluminal calculus is seen.
Lt. Ureter: Left ureter is visualized in its proximal segment. No evidence of dilatation. No intraluminal calculus is seen.
Urinary Bladder: Urinary bladder is adequately distended. Wall thickness appears normal. No intraluminal mass or debris is seen. Post-void residual urine is insignificant.
Prostate: Prostate volume is within normal limits. Echotexture appears homogeneous.
Free Fluid: No free fluid is seen in the abdomen or pelvis.

Other Observations: No abdominal lymphadenopathy identified. Visualized bowel loops are unremarkable. Appendix is not visualized; no sonographic evidence of acute appendicitis. Bilateral inguinal regions are unremarkable without hernia or significant lymphadenopathy.

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Measurement Summary:

Liver: 136 mm	Spleen: 95 mm
RK: 106 mm	LK: 112 mm
Prostate: 21 mL

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Impression: Prominent Riedel's lobe of the liver (normal anatomical variant). No focal hepatic lesion. Otherwise unremarkable ultrasound study of the abdomen and pelvis.

Recommendation: Clinical correlation advised.

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Limitations / Technical Factors: Ultrasound evaluation may not detect subtle bowel or early parenchymal abnormalities. Correlation with clinical findings is recommended.

• This report and accompanying images are not valid for medico-legal purposes.

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Riedel's Lobe – Ultrasound Diagnosis and Scanning Technique

1. Riedel’s lobe is:
A. Liver cyst
B. Hepatic tumor
C. Tongue-like extension of right lobe
D. Gallbladder anomaly

2. Riedel’s lobe most commonly arises from:
A. Right hepatic lobe
B. Left hepatic lobe
C. Caudate lobe
D. Quadrate lobe

3. On ultrasound, Riedel’s lobe usually has:
A. Anechoic appearance
B. Calcification
C. Mixed cystic-solid pattern
D. Normal liver echotexture

4. Riedel’s lobe may be mistaken for:
A. Renal stone
B. Hepatomegaly or abdominal mass
C. Pleural effusion
D. Pancreatitis

5. The best scan plane to demonstrate its inferior extension is:
A. Thyroid transverse
B. Pelvic sagittal
C. Longitudinal/subcostal liver scan
D. Cardiac apical view

6. A key feature confirming Riedel’s lobe is:
A. Separate from liver
B. Fluid-filled structure
C. Calcified margin
D. Continuity with liver parenchyma

7. Color Doppler typically shows:
A. Normal hepatic vessels
B. No blood flow
C. Chaotic neovascularity
D. Portal vein thrombosis

8. During scanning, the transducer should be extended:
A. Toward the neck
B. Inferiorly below right costal margin
C. Only across the spleen
D. To the pelvis only

9. The main importance of recognizing Riedel’s lobe is:
A. Diagnose cirrhosis
B. Diagnose hepatitis
C. Avoid misdiagnosis as a mass
D. Detect ascites

10. In most cases Riedel’s lobe is considered:
A. Malignant lesion
B. Congenital normal variant
C. Abscess
D. Metastatic disease

Answer Key:

1-C, 2-A, 3-D, 4-B, 5-C,
6-D, 7-A, 8-B, 9-C, 10-B