What is adenomyomatosis of the gallbladder?

Adenomyomatosis of the Gallbladder

Adenomyomatosis of the gallbladder is a benign, degenerative condition characterized by mural hyperplasia with epithelial proliferation and hypertrophy of the muscularis propria, resulting in outpouchings of mucosa called Rokitansky-Aschoff sinuses. 1

Definition and Pathophysiology

• Adenomyomatosis is defined as mural hyperplasia that may be diffuse, focal, or segmental with characteristic imaging findings including comet-tail artifacts (on grayscale imaging) or twinkling artifacts (on color Doppler imaging) due to intramural cholesterol crystals 2
• The condition involves excessive epithelial proliferation with hypertrophy of the muscular layer, leading to mucosal invaginations through the thickened muscularis forming intramural diverticula known as Rokitansky-Aschoff sinuses 1, 3
• The pathogenesis remains unknown, though chronic inflammation of the gallbladder is considered a necessary precursor 4

Classification

• Three distinct morphological types are recognized 1:
  • Fundal: Focal thickening involving only the gallbladder fundus
  • Segmental: Circumferential wall overgrowth leading to compartmentalization
  • Diffuse: Disseminated thickening and irregularity throughout the mucosa and muscularis

Epidemiology

• Adenomyomatosis commonly occurs in middle-aged individuals with equal sex distribution 1
• Prevalence in cholecystectomy specimens ranges from 1% to 9%, with incidence increasing after age 50 4
• The condition can occur rarely in children, as documented in pediatric case reports 3

Clinical Presentation

• Most patients with adenomyomatosis remain asymptomatic, with the condition often discovered incidentally during imaging for other reasons 5
• When symptomatic, patients typically present with:
  • Right upper quadrant pain or dull discomfort 6
  • Hepatic colic, even in the absence of gallstones 4
  • Rarely, acute acalculous cholecystitis 4
• Gallstones are commonly associated (50-90% of cases) but not necessary for symptom development 4

Diagnosis

• Ultrasound is the initial imaging modality of choice 7, with characteristic findings including:
  • Thickened gallbladder wall containing small cystic spaces (Rokitansky-Aschoff sinuses)
  • "Comet-tail" artifacts on grayscale imaging 2, 1
  • "Twinkling" artifacts on color Doppler imaging 2, 1
• If differentiation between tumefactive sludge and adenomyomatosis is challenging:
  • Short-interval follow-up ultrasound within 1-2 months with optimized technique is recommended 8
  • Higher sensitivity Doppler techniques such as power Doppler and B-Flow may help differentiate 2
• Advanced imaging options when uncertainty persists:
  • Contrast-enhanced ultrasound (CEUS) can distinguish vascular lesions from sludge 7, 8
  • MRI with cholangiography sequences shows characteristic "pearl-necklace sign" and has extremely high sensitivity for identifying Rokitansky-Aschoff sinuses 7, 1
  • CT is less accurate than CEUS or MRI but may show a "rosary sign" 8, 1

Management

Symptomatic Adenomyomatosis

• Cholecystectomy is the recommended treatment for symptomatic adenomyomatosis of any type, with laparoscopic approach being the standard of care 7, 4
• Surgical risk is minimal with cholecystectomy, with morbidity of 2-8% 7, 8
• Risk of bile duct injury during cholecystectomy is approximately 0.3-0.6% 7, 8
• Cholecystectomy results in complete resolution of symptoms 4

Asymptomatic Adenomyomatosis

• Management depends on the type of adenomyomatosis 1:
  • Fundal type: Can be safely observed with ultrasound
  • Segmental type: Cholecystectomy may be considered due to increased risk of malignancy
  • Diffuse type: Cholecystectomy may be considered due to difficulty visualizing any coexisting malignancy
• The Society of Radiologists in Ultrasound (SRU) consensus suggests that extended follow-up beyond 3 years is not productive 7, 8

Relationship to Malignancy

• While adenomyomatosis is generally benign, there are rare associations with dysplastic changes and cancer, particularly in the context of chronic inflammation and lithiasis 3
• In cases of diagnostic doubt regarding possible malignancy, cholecystectomy is justified 4
• The segmental type carries a higher risk of malignancy compared to other types 1

Special Considerations

• For pregnant patients with symptomatic adenomyomatosis:
  • Laparoscopic cholecystectomy is safe during pregnancy regardless of trimester, ideally performed in the second trimester 7
  • For late third-trimester presentations, postponing surgery until after delivery may be reasonable if it doesn't pose risk to maternal or fetal health 7