# Differentiation of Gallbladder Adenomyomatosis and Polyps in a Western Cohort: Prevalence, Ultrasound Characteristics, and Diagnostic Challenges

## TL;DR

This study examines how ultrasound can distinguish between benign gallbladder conditions and cancer-like lesions in a large group of patients, showing most cases are harmless and don't require surgery.

## Contribution

The study provides a detailed ultrasound-based differentiation of gallbladder adenomyomatosis and polyps in a large cohort, emphasizing their benign nature and diagnostic accuracy.

## Key findings

- Adenomyomatosis was diagnosed in 1.2% of patients with specific ultrasound features like thickened walls and RAS.
- Gallbladder polyps were found in 4.6% of patients, with most remaining stable and only three requiring surgery.
- Only one case of adenomyomatosis and one precancerous polyp were identified, highlighting the benign nature of most findings.

## Abstract

Gallbladder adenomyomatosis and polyps are common benign lesions that can mimic malignancy on imaging, often leading to unnecessary cholecystectomy. Despite frequent sonographic detection, the prevalence of adenomyomatosis in living cohorts remains poorly defined.

To determine the prevalence and characterize the sonographic features of gallbladder adenomyomatosis and polyps in a large unselected cohort, and to assess clinical relevance.

We retrospectively analyzed 2674 patients (≥ 16 years) who underwent abdominal ultrasound over 20 months. Examinations were performed by highly experienced sonographers using B‐mode, color Doppler, superb microvascular imaging and contrast‐enhanced ultrasound. Adenomyomatosis and polyps were classified based on morphology, wall involvement, vascularity, and Rokitansky–Aschoff sinuses (RAS). Follow‐up imaging was available in 68 of 123 patients with polyps (median 76 months).

Adenomyomatosis was diagnosed in 32 patients (1.2%). Characteristic features included hypoechoic or isoechoic thickened wall with anechoic or microlith‐filled RAS, often producing comet‐tail and twinkling artifacts. Only one patient required cholecystectomy due to symptomatic diffuse disease. Gallbladder polyps were identified in 123 patients (4.6%). Most polyps remained stable or showed minimal growth, with only three patients undergoing surgery, revealing two cholesterol polyps and one precancerous intracholecystic papillary neoplasm (0.04% of the total cohort).

Structured, high‐quality ultrasound enables reliable differentiation of adenomyomatosis and benign polyps from lesions suspicious for malignancy. The vast majority of findings are benign, supporting conservative management. These results provide a reference standard for sonographic assessment and emphasize the importance of awareness and systematic evaluation of gallbladder wall abnormalities.