Biliary Malignancy Mimicking Cholecystitis: A Multimodality Imaging Case Series

Background:
Biliary malignancy may present with clinical and imaging findings resembling cholecystitis, making preoperative diagnosis challenging. Failure to recognize an underlying malignancy may affect surgical planning, require additional procedures, and delay appropriate oncologic staging and treatment. We present two cases of biliary malignancy initially diagnosed as cholecystitis and discuss the potential role of multimodality imaging in identifying features that may raise suspicion for malignancy.

Methods:
We retrospectively reviewed two patients who presented with clinical and imaging findings suggestive of cholecystitis and underwent planned laparoscopic cholecystectomy. Initial ultrasound and computed tomography (CT) examinations, postoperative histopathological findings, subsequent imaging, including fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), and clinical course were reviewed. Particular attention was given to imaging findings that may retrospectively suggest an underlying malignant process.

Results:
In both patients, the initial clinical and radiological diagnosis was cholecystitis, with no preoperative suspicion of malignancy. Both underwent laparoscopic cholecystectomy, and malignancy was unexpectedly diagnosed on postoperative histopathological examination. The diagnosis prompted additional oncologic staging and the need for further radical surgical management. Subsequent 18F-FDG PET/CT demonstrated metastatic disease, significantly altering further management. Retrospective assessment of the initial examinations was performed to identify imaging features that might have raised suspicion for malignancy before the initial surgery.

Conclusions:
Biliary malignancy can closely mimic cholecystitis on both clinical presentation and initial imaging. Unexpected malignancy following cholecystectomy may necessitate additional surgery and may reveal more advanced disease at subsequent staging. Careful assessment of atypical or suspicious imaging features and correlation across imaging modalities may help identify patients who require further evaluation before surgery and potentially improve initial staging and treatment planning.