This case illustrates how difficult it can be to assess the gallbladder when there is anatomical distortion due to cholesterolosis/adenomyomatosis and sludge. It is difficult to ascertain if the 11 polyp at the fundus was part of the wall hypertrophy distortion or a true polyp.

CEUS has a well-established use for the assessment of focal liver lesions and, similar to this case, to differentiate gallbladder sludge from a mass. This study reassured no evidence of sizable suspicious lesions in the gallbladder.

6 months follow-up scan (not shown) showed stability of the findings but given stated 11 mm polyp, which was stable, the surgical review recommended removal of the gallbladder. The risk of underlying malignancy was discussed (see guidelines for gallbladder polyp management), the patient was offered cholecystectomy: 

Macroscopy: Labeled "gallbladder". Gallbladder, 78 x 30 x 23 mm the cystic duct is clamped. A cystic duct node is not identified. The serosal surface is smooth. The gallbladder wall is tan, up to 3 mm in thickness. The mucosa is green, velvety, with frequent yellow speckling, forming polyps, up to 4 mm in diameter. Within the lumen, innumerable yellow fragments of debris from similar polyps.

Microscopy: Gallbladder shows smooth muscle hypertrophy and fibrosis and Rokitansky Aschoff sinus formation. Patchy chronic inflammation. A cholesterol polyp is seen with subepithelial foamy macrophage deep to the surface epithelium. No malignancy. 

Conclusion: Gallbladder–chronic cholecystitis, cholesterolosis, cholesterol polyp.

Please note that in this case, the sonographic features are those of likely multiple cholesterol polyps (cholesterolosis) and possible adenomyomatosis (further characterized on histology).

Adenomyomatosis: mucosal hyperplasia with growth toward the muscular layer - thickened muscular layer. Cholesterol accumulation is intraluminal (within the Rokitansky-Aschoff sinuses), therefore, lined by mucosal epithelium. 

Cholesterolosis: mucosal hyperplasia with the accumulation of cholesterol esters and triglycerides in the lamina propria macrophages - appearance is known as “strawberry gallbladder".