What is gallbladder wall adenomyomatosis?

Gallbladder Wall Adenomyomatosis

Gallbladder adenomyomatosis (GA) is a benign degenerative and proliferative condition characterized by excessive epithelial proliferation with hypertrophy of the muscularis propria, forming intramural diverticula called Rokitansky-Aschoff sinuses (RAS). 1

Definition and Pathophysiology

Gallbladder adenomyomatosis involves:

• Proliferation of the mucosal epithelium with hypertrophy of the muscular layer
• Formation of outpouchings of mucosa into or beyond the muscle layer (Rokitansky-Aschoff sinuses)
• Thickened gallbladder wall containing small bile-filled cystic spaces 2

The bile contained within these sinuses may undergo concentration, leading to crystal precipitation and calcification development over time 2.

Types of Adenomyomatosis

Three distinct types are recognized 1:

1. Fundal type: Focal thickening involving the gallbladder fundus
2. Segmental type: Circumferential overgrowth of the gallbladder wall creating compartments
3. Diffuse type: Disseminated thickening and irregularity of the mucosa and muscularis throughout the gallbladder

Diagnostic Features

Ultrasound Findings

Ultrasound is the preferred imaging modality for detecting gallbladder adenomyomatosis 3, with characteristic features including:

• Thickened gallbladder wall with intramural cystic spaces
• "Comet-tail" artifacts on gray-scale imaging
• "Twinkling" artifacts on color Doppler imaging 4, 2

Other Imaging Modalities

When ultrasound findings are equivocal:

• Contrast-Enhanced Ultrasound (CEUS): Shows RAS as avascular structures regardless of content 2
• MRI: Reveals the "pearl-necklace sign" with high sensitivity 2
• CT: May show the "rosary sign" but is not routinely indicated 2

According to the Society of Radiologists in Ultrasound (SRU), adenomyomatosis is defined as "mural hyperplasia that may be diffuse, focal, or segmental with comet-tail artifact (at gray-scale imaging) or twinkling artifact (at color Doppler imaging) due to intramural cholesterol crystals; Rokitansky-Aschoff sinuses may appear as intramural cysts." 4

Clinical Significance and Management

Clinical Presentation

• Most patients with adenomyomatosis remain asymptomatic 5
• Some patients may experience right upper quadrant pain, particularly when not associated with gallstones 5

Management Recommendations

Management depends on symptoms and type of adenomyomatosis:

1. Symptomatic GA: Cholecystectomy is recommended for all symptomatic cases regardless of type 1

2. Asymptomatic GA:

   • Fundal type: Can be safely observed with ultrasound 1
   • Segmental type: Consider cholecystectomy due to increased risk of malignancy 1
   • Diffuse type: Consider cholecystectomy due to difficulty visualizing any coexisting malignancy 1

3. Uncertain diagnosis: Cholecystectomy should be offered to avoid overlooking malignancy 1

Follow-up Recommendations

For adenomyomatosis being monitored rather than surgically treated:

• Ultrasound is the preferred follow-up modality 3
• The optimal frequency and duration of monitoring remain undefined 1
• Extended follow-up beyond 3 years is generally not productive as most polyp-associated malignancies are identified within the first 3 years 3

Important Considerations

• Adenomyomatosis must be distinguished from gallbladder polyps and malignancy
• Diagnostic uncertainty warrants surgical consultation
• Laparoscopic cholecystectomy is the preferred surgical approach when indicated 3
• Pediatric cases are rare but have been reported, presenting with recurrent abdominal pain 6

The importance of correctly identifying adenomyomatosis lies in avoiding unnecessary cholecystectomies for benign conditions while ensuring appropriate surgical management for cases with malignancy risk or symptoms.