Adenomyomatosis

Adenomyomatosis is a benign hyperplastic cholecystosis. It is a relatively common condition (identified in at least 5% of cholecystectomy specimens). Most diagnoses are made in patients in their 50s. Adenomyomatosis is most often an incidental finding, has no intrinsic malignant potential, and usually requires no treatment. Cholesterolosis, the other hyperplastic cholecystosis, consists of deposition of triglycerides and cholesterol esters within the lamina propria, producing a characteristic gross appearance known as “strawberry gallbladder.” Cholesterol accumulation in adenomyomatosis is intraluminal, as cholesterol crystals precipitate in the bile trapped in Rokitansky-Aschoff sinuses (intramural diverticula lined by mucosal epithelium).

Gallbladder involvement by adenomyomatous hyperplasia is variable in extent and location, with heterogeneous imaging appearances corresponding to diffuse, segmental, and focal adenomyomatosis.

• • Exclusion of [gallbladder cancer] may be most problematic in segmental and focal cases
  • Focal adenomyomatosis may appear as a discrete mass, known as an adenomyoma.

• Echogenic intramural foci from which emanate V-shaped comet tail reverberation artifacts are highly specific for adenomyomatosis, representing the unique acoustic signature of cholesterol crystals within the lumina of Rokitansky-Aschoff sinuses.

Patient #1

• Abnormal gallbladder wall thickening and enhancement are common but nonspecific CT features of adenomyomatosis.
• Rokitansky-Aschoff sinuses of sufficient size can be visualized; a CT rosary sign has been described, formed by enhancing epithelium within intramural diverticula surrounded by the relatively unenhanced hypertrophied gallbladder muscularis.

• The pearl necklace sign alludes to the characteristically curvilinear arrangement of multiple rounded hyperintense intraluminal cavities visualized at T2-weighted MR imaging and MR cholangiopancreatography of adenomyomatosis.

Patient #2: MRI images demonstrate adenomyomatosis at the gallbladder fundus

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  T2 SSFSE
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  T2 SSFSE
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  LAVA post GAD
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  T2 fat sat

Metabolic characterization with PET may be a useful adjunct in problematic cases.

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