Case Study

Beaver Tail Liver

Beaver Tail Liver is an uncommon anatomical variant in which the left hepatic lobe extends laterally across the upper abdomen, often partially or completely surrounding the spleen. This elongated configuration may mimic splenic pathology or perisplenic collections on imaging studies. Recognition of this benign morphological variant is important to avoid diagnostic confusion and inadvertent injury during abdominal trauma assessment or surgical procedures.

Whole Abdomen & Pelvis Sonography

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.

Liver: Liver is normal in size and echotexture with elongated lateral extension of the left hepatic lobe wrapping around the spleen, consistent with Beaver Tail Liver (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.

Measurement Summary:

Liver Rt Lobe: 139 mm	Liver Lt Lobe: 92 mm	Spleen: 109 mm
RK: 114 mm	LK: 117 mm
Prostate: 13 mL

Impression: Beaver Tail Liver (elongated left hepatic lobe), a normal anatomical variant. No focal hepatic lesion. Otherwise unremarkable ultrasound study of the abdomen and pelvis.

Recommendation: Clinical correlation advised.

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.

Beaver Tail Liver MCQ Quiz

1. Beaver Tail Liver is:
A. A hepatic tumor
B. A congenital cyst
C. An elongated left hepatic lobe extending around the spleen
D. A gallbladder anomaly

2. Beaver Tail Liver primarily involves:
A. Right hepatic lobe
B. Left hepatic lobe
C. Caudate lobe
D. Quadrate lobe

3. On ultrasound, the extended lobe usually demonstrates:
A. Normal liver echotexture
B. Large calcifications
C. Multiple cysts
D. Gas echoes

4. Beaver Tail Liver may be mistaken for:
A. Splenic mass or perisplenic pathology
B. Renal stone
C. Pleural effusion
D. Pancreatic pseudocyst

5. The best ultrasound approach to evaluate this variant is:
A. Pelvic scan only
B. Thyroid scan
C. Left upper quadrant and intercostal scanning
D. Cardiac apical view

6. A key feature confirming Beaver Tail Liver is:
A. Separation from the liver
B. Fluid-filled appearance
C. Continuity with normal liver parenchyma
D. Presence of calcified walls

7. Color Doppler typically demonstrates:
A. Absence of blood flow
B. Normal hepatic and portal vessels within the extension
C. Chaotic neovascularity
D. Splenic infarction

8. During scanning, the transducer should be positioned to assess:
A. The neck region
B. The left upper abdomen near the spleen
C. Only the pelvis
D. Only the gallbladder

9. The clinical importance of recognizing Beaver Tail Liver is to:
A. Diagnose cirrhosis
B. Diagnose hepatitis
C. Avoid misdiagnosis of splenic or abdominal pathology
D. Detect gallstones

10. Beaver Tail Liver is generally considered:
A. Malignant lesion
B. Normal anatomical variant
C. Hepatic abscess
D. Metastatic disease

Answer Key:

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