Dropped Gall Stones and Differentials of Peritoneal Deposits | Radiology Board Review Case
Incidence and pathophysiology
- Spillage of gall stones in the peritoneal cavity causes “dropped” gall stones or retained gall stones.
- These are common with laparoscopic cholecystectomies, reported in up to 7 percent cases.
- Can act as an inflammatory nidus, especially pigment gall stones.
- Can migrate and lie outside the peritoneal cavity.
- Complications:
- Abscesses – Most commonly at the abdominal port sites and the perihepatic spaces.
- Fistulas
- Others.
Imaging features
- Location: Perihepatic spaces and pelvis
- CT – Small iso to hypodense nodular lesions. Stones with calcium content will appear hyperdense.
- MRI – Non-enhancing T1 hyperintense foci.
- Look for interval stability and history of laproscopic cholecystectomy.
- Often confused with peritoneal deposits as in the case illustrated above.
- Differentials include peritoneal metastasis, colonic diverticula, dropped appendicolith and peritoneal loose bodies AKA “peritoneal mice” (chronic torsion and auto-amputation of epiploic appendages causes these benign soft tissue nodules in the peritoneal cavity).
Management
Drainage of abscess and removal of all gall-stones. This can be usually be achieved by percutaneous drainage, if unsuccessful laparoscopy can be performed.
Differentials diagnosis of peritoneal nodules
- Peritoneal carcinomatosis
- Primary peritoneal mesothelioma
- Peritoneal tuberculosis
- Lymphoma
- Dropped gall-stones
- Splenosis
- Primary peritoneal mesothelioma
Reference and further reading
- Dropped gallstones: spectrum of imaging findings, complications and diagnostic pitfalls.
- Out of Sight but Kept in Mind: Complications and Imitations of Dropped Gallstones.
- Computed Tomography and Magnetic Resonance Imaging of the Whole Body by Haaga
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Dr. Amar Udare, MD, DNB
Dr. Amar Udare is a board-certified radiologist. He is a clinical assistant professor at the University of Calgary. He has a passion for teaching (#FOAMrad and #FOAMed) and has been a semi-finalist for the 2018 and 2020 Aunt-Minnie Most effective Radiology Educator Awards. He has authored multiple peer-reviewed publications which can be accessed on PubMed and Google Scholar.