Ultrasound of the Week
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UOTW #79

This patient is a 64 year old male with a history of a pancreatic mass who presents with worsening jaundice and mild abdominal pain. Physical exam reveals normal vital signs, notable jaundice and scleral icterus and mild epigastric tenderness to palpation and a negative Murphy’s sign. Bedside right upper quadrant ultrasound is shown below.

Answer

 

Answer: Adenomyomatosis of the gallbladder

  • Adenomyomatosis of the gallbladder is a hyperplastic growth of the internal wall of the gallbladder causing intramural diverticula.1
  • Cholesterol deposits are then trapped in the diverticula and are responsible for the comet tail artifacts seen on ultrasound.
  • Focal adenomyomatosis is a relatively common finding seen in about 9% of all cholecystectomy specimens.2
  • Thought to be a reactive change secondary to chronic inflammation.
  • Difficult to differentiate from malignancy so sometimes leads to cholecystectomy.3
  • Initially can be confused with emphysematous cholecystitis (as I initially thought in this patient).  Cholesterol crystals however give a characteristic V-shaped comet tail as opposed to a linear reverberation artifact or “dirty” shadow of emphysematous cholecystitis.
  • If unsure of diagnosis, CT scan is more specific for emphysematous cholecystitis.4
See also
  1. Boscak AR, Al-hawary M, Ramsburgh SR. Best cases from the AFIP: Adenomyomatosis of the gallbladder. Radiographics. 2006;26(3):941-6.
  2. Poonam Y, Ashu S, Rohini G. Clinics in diagnostic imaging (121). Gallbladder adenomyomatosis. Singapore Med J. 2008;49(3):262-4.
  3. Raghavendra BN, Subramanyam BR, Balthazar EJ, Horii SC, Megibow AJ, Hilton S. Sonography of adenomyomatosis of the gallbladder: radiologic-pathologic correlation. Radiology. 1983;146(3):747-52.
  4. Sunnapwar A, Raut AA, Nagar AM, Katre R. Emphysematous cholecystitis: Imaging findings in nine patients. Indian J Radiol Imaging. 2011;21(2):142-6.