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: 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