What is gallbladder adenomyomatosis and what are its associated risks, including malignant transformation?

What is Adenomyomatosis and Its Associated Risks

Adenomyomatosis is a benign hyperplastic condition of the gallbladder wall with extremely low to negligible malignant potential that does not require routine surveillance or prophylactic surgery in asymptomatic patients. 1

Definition and Pathophysiology

Adenomyomatosis is characterized by mural hyperplasia (benign overgrowth) of the gallbladder wall with proliferation of surface epithelium that invaginates into the wall, forming distinctive structures called Rokitansky-Aschoff sinuses (RAS). 1, 2 These sinuses are bile-filled cystic spaces that may contain cholesterol crystals, which produce characteristic imaging artifacts. 3

The condition can manifest in three patterns: 1, 2

• Diffuse: affecting the entire gallbladder
• Segmental: affecting a portion of the gallbladder
• Focal/localized: affecting a discrete area (most commonly the fundus)

Diagnostic Features

The diagnosis relies on identifying characteristic imaging findings that distinguish adenomyomatosis from true gallbladder polyps and malignancies:

Ultrasound findings include: 3, 1

• Comet-tail artifact on gray-scale imaging
• Twinkling artifact on color Doppler imaging (due to intramural cholesterol crystals)
• Intramural cysts representing Rokitansky-Aschoff sinuses
• Gallbladder wall thickening

Contrast-enhanced ultrasound (CEUS) demonstrates avascular Rokitansky-Aschoff sinuses, which is a key distinguishing feature from neoplastic lesions that show marked early enhancement. 3, 1

Risk Assessment: Malignant Transformation

The malignant potential of adenomyomatosis is extremely low and does not justify prophylactic surgery or routine surveillance. 1 This represents the consensus position based on current evidence:

• Adenomyomatosis is explicitly categorized as a benign entity by the Society of Radiologists in Ultrasound 2022 guidelines. 1
• A recent 2026 study with median follow-up of 35 months found zero cases of gallbladder carcinoma development among 144 patients with adenomyomatosis. 4
• The condition lacks the risk factors that would warrant prophylactic surgery (unlike calcified gallbladders or stones >3 cm). 1

Important caveat: While adenomyomatosis itself is benign, it can be associated with chronic cholecystitis, which is a known risk factor for gallbladder cancer. 4 However, this association does not change the management approach for adenomyomatosis itself.

Clinical Significance and Symptoms

Most patients with adenomyomatosis remain asymptomatic, and the condition is typically an incidental finding on imaging. 5, 6 When symptoms occur, they manifest as: 5

• Right upper quadrant pain
• Biliary-type pain (steady, severe, lasting >15 minutes, unaffected by position or antacids)

Critical distinction: Belching, bloating, fatty food intolerance, and chronic diffuse pain are NOT attributable to gallbladder disease and should not prompt cholecystectomy. 1

Management Algorithm

For symptomatic patients (with true biliary-type pain): 1

• Laparoscopic cholecystectomy is the preferred approach
• Particularly appropriate for patients aged 40-50 years with lower surgical risk
• Surgery provides meaningful quality of life benefit when symptoms are clearly attributable to biliary disease

For asymptomatic patients: 1, 4

• Expectant management is recommended
• The benign natural history does not justify prophylactic surgery
• Recent evidence (2026) confirms that follow-up is not needed for lesions with clear diagnosis of focal adenomyomatosis, even for larger lesions. 4

Exception requiring immediate action: If there is any suspicion for invasive or malignant tumor (frank liver invasion, focal wall thickening ≥4 mm adjacent to mass, sessile morphology), immediately refer to an oncologic specialist rather than following routine algorithms. 7

Size Considerations

Lesion size does not influence management decisions for adenomyomatosis. 4 A 2026 study comparing lesions above and below 1.5 cm found:

• No statistically significant correlation between size and clinical characteristics
• No difference in growth rates between larger and smaller lesions
• Only 9 of 144 lesions showed any growth during follow-up (not statistically significant)
• Zero malignant transformations regardless of size

Common Pitfalls to Avoid

Misdiagnosis as gallbladder polyp or malignancy: 3, 1

• Always look for characteristic comet-tail or twinkling artifacts
• Confirm presence of Rokitansky-Aschoff sinuses on imaging
• Use CEUS to demonstrate avascularity if diagnosis is uncertain

Unnecessary cholecystectomy: 1

• Do not operate on asymptomatic patients
• Ensure symptoms are truly biliary in nature before recommending surgery
• Recognize that vague gastrointestinal symptoms are not indications for surgery

Inappropriate surveillance: 4

• Recent evidence does not support routine follow-up imaging for clearly diagnosed adenomyomatosis
• Surveillance protocols proposed in older studies are not supported by current data