Adenomyomatosis of the Gallbladder
Adenomyomatosis of the gallbladder is a benign, degenerative condition characterized by proliferation of the mucosal epithelium and hypertrophy of the muscularis propria, forming characteristic Rokitansky-Aschoff sinuses (RAS) that penetrate through the thickened muscular layer. 1, 2
Definition and Pathology
- Adenomyomatosis is defined as mural hyperplasia of the gallbladder that may present in three distinct patterns: diffuse, focal (fundal), or segmental 1
- The condition is characterized by excessive epithelial proliferation with hypertrophy of the muscularis propria, creating outpouchings of mucosa (Rokitansky-Aschoff sinuses) that extend into or beyond the muscle layer 2
- The pathogenesis remains unknown, though chronic inflammation of the gallbladder appears to be a necessary precursor 3
- Adenomyomatosis commonly occurs in middle age with equal sex distribution, with increasing incidence after age 50 2, 3
Types of Adenomyomatosis
- Fundal type: Focal thickening involving only the gallbladder fundus 2
- Segmental type: Circumferential overgrowth of the gallbladder wall leading to formation of compartments 2
- Diffuse type: Disseminated thickening and irregularity of the mucosa and muscularis throughout the gallbladder (the rarest form) 2, 4
Clinical Presentation
- Most patients with adenomyomatosis remain asymptomatic, with the condition often discovered incidentally during imaging or in surgical specimens 5
- When symptomatic, patients typically present with right upper quadrant pain or hepatic colic, even in the absence of gallstones 3
- Gallstones are commonly associated with adenomyomatosis, occurring in 50-90% of cases 3
- Adenomyomatosis can occasionally present as acalculous cholecystitis 3
- Pediatric cases are rare but can occur, presenting with recurrent abdominal pain 6
Diagnostic Approach
- Ultrasound (US) is the initial imaging modality of choice for diagnosis 1, 7
- Characteristic ultrasound findings include:
- If differentiation between tumefactive sludge and adenomyomatosis is challenging, short-interval follow-up US within 1-2 months with optimized technique is recommended 7, 8
- Advanced imaging options include:
- Contrast-enhanced ultrasound (CEUS) to distinguish vascular lesions from sludge 1, 7
- MRI with cholangiography sequences, which shows the characteristic "pearl-necklace sign" and has extremely high sensitivity for identifying Rokitansky-Aschoff sinuses 1, 7
- CT has inferior diagnostic accuracy compared to CEUS or MRI 7, 8
Management Recommendations
- Cholecystectomy is the recommended treatment for symptomatic adenomyomatosis of any type, with laparoscopic approach being the standard of care 1, 7
- For asymptomatic adenomyomatosis:
- The Society of Radiologists in Ultrasound (SRU) consensus suggests that extended follow-up beyond 3 years is not productive 1, 8
- Cholecystectomy may be considered for segmental type due to increased risk of malignancy and for diffuse type due to difficulty visualizing any coexisting malignancy 2
- Asymptomatic fundal adenomyomatosis can be safely observed with ultrasound 2
- Surgical considerations:
- Surgical risk with cholecystectomy is minimal, with morbidity of 2-8% 1, 7, 8
- Risk of bile duct injury during cholecystectomy is approximately 0.3-0.6% 1, 7, 8
- For pregnant patients with symptomatic adenomyomatosis, laparoscopic cholecystectomy is safe during pregnancy regardless of trimester, ideally performed in the second trimester 1, 7
Important Clinical Considerations
- Although adenomyomatosis is generally benign, lithiasis and chronic inflammation may rarely lead to dysplastic changes and cancer 6, 2
- If there is any diagnostic doubt about the possibility of gallbladder cancer, cholecystectomy is justified 3
- The discovery of adenomyomatosis in a cholecystectomy specimen does not require special surveillance 3