Gallbladder lesions identified on ultrasound. Lessons from the last 10 years

Possible mass lesions identified on ultrasound (US) of the gallbladder may prompt an aggressive surgical intervention due to the possibility of a malignant neoplasm.

This study aims to utilize a large modern series of patients with gallbladder lesions identified on US to evaluate imaging characteristics consistent with malignancy.

A retrospective review was conducted of gallbladder ultrasound reports and clinicopathologic data of patients with a mass identified on US.

Approximately 59,271 abdominal ultrasounds and 9,117 cholecystectomies were performed between February 2000 and February 2010. We identified 213 patients with a questionable gallbladder neoplasm on ultrasonography who underwent surgical exploration. Median age was 52 years (range=11-87 years) and 147 (69%) were females. Final pathology demonstrated no neoplasm in 130 patients (61%), while 32 patients (15%) had a wall adenomyoma, 36 (17%) had a polyp (five of which were malignant), 14 (7%) had an adenocarcinoma not arising from a polyp, and one patient had a cystic papillary neoplasm. The smaller the lesion, the more likely it was to be a pseudo-mass. For lesions measuring <5 mm on US, 83% had no lesion found on final pathology. Significant predictors of malignancy were age >52 years (p<0.001), presence of gallstones on US (p=0.004), size >9 mm (p<0.001), evidence of invasion at the liver interface (p<0.001), and wall thickening >5 mm (p<0.001). Shape (sessile or penduculated), echogenicity (echogenic or isoechoic), or presence of flow on Doppler were not predictors of malignancy. An US size of ≤ 9 mm had a negative predictive value of 100% for malignancy.

Despite improvements in imaging, most apparent lesions measuring <5 mm on US are not identified in the surgical specimen. US size >9 mm, age >52 years, US suggestion of invasion at the liver interface, and wall thickening >5 mm, especially in the presence of gallstones, should raise the suspicion of malignancy.