Adenomyomatosis
Adenomyomatosis is a benign, non-inflammatory condition of the gallbladder wall in which the inner lining grows into the muscle layer, forming small pouches called Rokitansky-Aschoff sinuses, often accompanied by thickening of the wall and small cholesterol crystals. It is a common incidental finding on abdominal imaging and rarely causes symptoms on its own. Adenomyomatosis is benign and is not considered a precursor of gallbladder cancer in the vast majority of patients. Ultrasound, MRI, and CT are the central tools for diagnosis, and most cases require no specific treatment.
What is it?
The gallbladder wall is composed of an inner lining (mucosa), a muscle layer (muscularis), and outer connective tissues. Adenomyomatosis is a benign, non-inflammatory condition of this wall in which the mucosa grows into and through the muscle layer, forming small pouches or outpouchings known as Rokitansky-Aschoff sinuses. The muscle layer often thickens, and small cholesterol crystals frequently collect within these sinuses, producing a characteristic appearance on imaging. Adenomyomatosis is sometimes also called adenomyomatous hyperplasia of the gallbladder.
Adenomyomatosis is generally divided into three patterns based on its distribution within the gallbladder. The localized (or focal) form usually involves the fundus (the rounded end of the gallbladder) and appears as a focal mass or wall thickening; this is the most common pattern. The segmental form involves a band-like area of wall thickening, often producing a characteristic narrowing or “hourglass” deformity of the gallbladder; this pattern is more often seen in middle-aged and older adults. The diffuse form involves much of the gallbladder wall and is less common. The pattern often does not change the underlying nature of the condition, which is uniformly benign, but it can affect how the lesion appears on imaging.
The exact cause of adenomyomatosis is not fully understood. Possible contributors include chronic increased pressure within the gallbladder, gallbladder dyskinesia, and prolonged or repeated irritation from stones or other factors. Adenomyomatosis is more common in women and increases with age. It is commonly associated with gallstones, which are present in a substantial number of patients with adenomyomatosis, although the two conditions are not always related and either can occur alone.
Most patients with adenomyomatosis have no symptoms, and the condition is typically discovered incidentally during imaging or after surgery performed for other reasons. When symptoms occur, they are usually mild and nonspecific—such as vague upper right abdominal discomfort, mild pain after fatty meals, bloating, or nausea. In many cases where symptoms occur in a patient with adenomyomatosis, the symptoms are actually due to coexisting gallstones or other conditions rather than adenomyomatosis itself.
The most important clinical point about adenomyomatosis is that it is benign. It is not a precursor to gallbladder cancer in the vast majority of patients. Some uncertainty has historically existed about whether segmental adenomyomatosis, particularly in older adults, might be associated with a small increased risk of gallbladder cancer, but current evidence does not consistently support this in most populations, and modern imaging is generally effective at distinguishing benign adenomyomatosis from malignant gallbladder disease.
Diagnosis is usually made through imaging, and the appearance can be highly characteristic. Ultrasound is often the first study and may show focal or diffuse gallbladder wall thickening, intramural cystic spaces, and small bright echogenic foci with characteristic “comet-tail” artifacts produced by tiny cholesterol crystals in the Rokitansky-Aschoff sinuses. MRI with MR cholangiopancreatography (MRCP) is particularly useful and can show the classic “pearl necklace sign,” in which the intramural sinuses appear as a row of small, bright, fluid-filled spaces along the gallbladder wall on heavily T2-weighted imaging. CT can show wall thickening and intramural cysts but is generally less specific than MRI. In atypical cases—particularly when the imaging features overlap with chronic cholecystitis or gallbladder cancer—additional imaging or, rarely, surgical pathology may be needed for definitive diagnosis.
Important to Know
For most patients with adenomyomatosis, no specific treatment is needed. The condition is benign, generally stable over time, and rarely causes symptoms on its own. Once the diagnosis is confidently established by imaging, the most important step is reassurance and clear documentation of the finding in the medical record, so that the same imaging findings are not misinterpreted on future scans or used to recommend unnecessary procedures.
Patients with adenomyomatosis can usually maintain normal diet, exercise, and activity levels without restriction. There is no need to avoid alcohol or specific foods solely because of adenomyomatosis, although general healthy habits—such as a balanced diet, regular activity, weight management, and avoiding rapid weight loss—support overall gallbladder and metabolic health.
In selected patients with persistent, well-characterized symptoms (such as recurrent biliary-type pain) that cannot be explained by gallstones, other gallbladder disease, or alternative diagnoses, laparoscopic cholecystectomy may be considered. Decisions are individualized and made after careful evaluation, often including consultation with a gastroenterologist or hepatobiliary surgeon. When cholecystectomy is performed for symptomatic gallstones and adenomyomatosis is also present, the adenomyomatosis is generally addressed by the same procedure.
Cholecystectomy is also considered in patients in whom imaging cannot reliably distinguish adenomyomatosis from gallbladder cancer or other concerning findings. This is uncommon with modern imaging, but in select cases—such as significant focal wall thickening with atypical features, irregular masses, or other suspicious findings—surgery provides both definitive diagnosis and treatment.
Patients with adenomyomatosis and coexisting gallstones are managed according to standard principles for gallstone disease. Symptomatic gallstones generally warrant cholecystectomy, while asymptomatic gallstones in most patients do not require treatment, regardless of whether adenomyomatosis is also present.
Surveillance imaging for adenomyomatosis itself is generally not required in most asymptomatic patients with a confident diagnosis. In selected patients—such as those with atypical imaging features or where there is diagnostic uncertainty—periodic follow-up may be appropriate, with intervals individualized based on the specific findings and overall clinical context.
Care is typically coordinated by primary care clinicians and, when relevant, radiologists, gastroenterologists, and general or hepatobiliary surgeons. Imaging findings are interpreted alongside the patient’s symptoms, examination, and broader clinical context rather than in isolation.
Although adenomyomatosis itself is a benign and usually asymptomatic finding, any new abdominal symptoms should be evaluated based on their own clinical features rather than automatically attributed to a previously identified adenomyomatosis. Coexisting gallstones, cholecystitis, or other biliary or pancreatic conditions can occur and should be considered.
Red flag symptoms include severe persistent upper right or central abdominal pain, high fever with chills, persistent vomiting, jaundice (yellowing of the skin or eyes), dark urine, pale stools, signs of severe infection or shock, severe upper abdominal pain radiating to the back, confusion, or signs of gastrointestinal bleeding. These warrant prompt or urgent medical evaluation, as they may indicate complications of gallstone disease (such as cholecystitis, cholangitis, or pancreatitis) or other serious abdominal conditions, even when adenomyomatosis is also present.