Case:
55-year-old female with remote history of Roux-en Y gastric bypass presented to the ED for epigastric pain and nausea. On exam, she was noted to have tenderness to palpation in the epigastric area and right upper quadrant with a positive Murphy’s sign. Her abdomen was otherwise soft and non-distended. A point-of-care ultrasound of the gallbladder was preformed, showing the following
Case conclusion:
Given the finding of an echogenic, non-shadowing mass within the gallbladder, a CT of the abdomen was ordered. The CT was significant for:
1) a large heterogenous lesion in the right lobe of the liver with multiple associated subcentimeter lesions
2) a distended gallbladder with lobular, heterogeneous material representing tumefactive sludge (i.e. a sludge ball) vs gallbladder neoplasm, without evidence of stones or acute cholecystitis
The patient was evaluated by bariatric surgery, but was determined to have no acute surgical needs.
She was ultimately admitted to the medical service and had an MRI on hospital day 1 that confirmed the CT findings but as unable to further distinguish between a sludge ball and mass. On HD 3, an IR guided biopsy of the liver mass was performed. Preliminary pathology is concerning for undifferentiated adenocarcinoma, potentially of gallbladder origin.
Pearls:
On occasion, a RUQ ultrasound to evaluate for cholelithiasis/acute cholecystitis may reveal gallbladder abrnoamitiles other than stones or simple layering sludge. The differential of these masses should include the following:
Polyps: non-mobile, echogenic, non-shadowing masses that extend from the gallbladder wall on a stalk. They generally measure <1-2 cm in size and the associated wall should be normal in appearance. Patients found to have polyps should be given follow up for monitoring with serial ultrasounds and consideration for cholecystectomy if polyps are >1cm, as those are thought to have a higher rate of progression to malignancy.
Adenomyomatosis: caused by cholesterol deposition within the gallbladder wall, it appears as a thicken wall with echogenic foci that cause comet tail artifact and may or may not have a cystic appearance.
Tumifactive sludge: caused by coalescing of highly viscous sludge, tumifactive sludge will appear as a polypoid, echogenic, non-shadowing mass within the gallbladder lumen (a sludge ball) and can appear very similar to a tumor. Tumifactive sludge should not have internal vascularity and may or may not be mobile. However, it can be challenging to differentiate from a malignancy and therefore requires followup, either with US or MRI, to determine if there is decrease in size or resolution of the mass, which would rule out a neoplasm.
Malignancy: primary gallbladder carcinomas are rare, but the vast majority of gallbladder malignancies are primary carcinomas. Malignancy will typically have a heterogenous appearance and internal vascularity with an associated irregular gallbladder wall. Destruction of the wall and invasion into the liver or other surrounding structures may be seen. These patients need follow up imaging with CT or MRI for staging.
Bottom line, if you have a patient with a large polyp or an intraluminal mass, such as the patient in this case, follow up with serial ultrasound or other advanced imaging is necessary to help differentiate neoplastic from benign conditions.
-Allison Zanaboni, MD, Emergency Medicine Ultrasound Fellow
References:
McKnight, Timothy, and Ankit Patel. “Gallbladder Masses: Multimodality Approach to Differential Diagnosis.” Journal of the American Osteopathic College of Radiology, 9 Oct. 2012, www.aocr.org/?page=z162.
Fitzgerald, E. J., and A. Toi. “Pitfalls in the Ultrasonographic Diagnosis of Gallbladder Diseases.” Postgraduate Medical Journal, vol. 63, no. 741, 1987, pp. 525–532., doi:10.1136/pgmj.63.741.525.
Kim, Mimi, et al. “Tumefactive Gallbladder Sludge at US: Prevalence and Clinical Importance.” Radiology, vol. 283, no. 2, 2017, pp. 570–579., doi:10.1148/radiol.2016161042.
Boscak, A, et al. “Adenomyomatosis of the Gallbladder.” RadioGraphics , vol. 26, no. 3, 2006, doi:https://doi.org/10.1148/rg.263055180.