Gallbladder Cancer
Fast Facts:
- Most common biliary tract malignancy.
- Extremely lethal if symptomatic at presentation (mean survival ≈ 6 months).
- Associated with gallstones and chronic inflammation (incidentally found at surgery in ≈ 2% of routine cholecystectomy patients).
PET/CT Interpretation of Gallbladder Activity:
The normal gallbladder typically demonstrates little or no FDG uptake.
Mild to moderate diffuse gallbladder uptake is usually normal.
Intense diffuse gallbladder uptake in an otherwise normal appearing gallbladder often represents normal physiologic uptake. Ultrasound correlation, however, is still typically recommended: “Ultrasound correlation may be of diagnostic value, if clinically warranted.”
Diffuse intense gallbladder uptake associated with wall thickening, pericholecystic fluid or gallstones is suspicious for cholecystitis. In such cases, ultrasound correlation is strongly recommended, “Ultrasound correlation is recommended in this case to exclude acute cholecystitis.”
While focal intense gallbladder wall uptake can be seen with benign polyps, adenomyomatosis or focal inflammation associated with cholecystitis, malignancy must be excluded.
False Positives:
- Normal Physiologic Uptake
- Polyps & Adenomyomatosis
- Cholcystitis, Acute or Chronic
Indications for PET/CT:
Initial Staging of Gallbladder Carcinoma:
- While PET/CT can detect the primary lesion, its true utility lies in the detection of regional nodes and distant metastatic disease.
- Distant Disease: Most commonly to the liver, lung and brain.
Assessing Response to Therapy & Prognosis:
- Early Response: Non-responders can be offered alternative therapy.
- Late Response: Assess success or failure of therapy, and ultimate outcome.
Recurrence & Restaging:
- Restaging suspected recurrence.
- Distinguishing recurrence from post-therapeutic inflammation.
Case 1
Case 2
Case 2 (Image 2)
Axial images localize this uptake to the gallbladder. Such uptake, without an associated soft tissue abnormality on the CT images, represents normal physiologic uptake. Typically, the gallbladder is partially contracted on the CT images (due to oral contrast administration), mildly limiting its evaluation.
Case 3
Case 3 (Image 2)
Axial images localize this uptake to the gallbladder. Such uptake, without an associated soft tissue abnormality on the CT images, represents normal physiologic uptake.
Case 4
Case 4 (Image 2)
Axial images localize this uptake to the gallbladder fossa. Surgical clips are present (arrow), secondary to cholecystectomy 4-weeks previously. FDG uptake in this case reflects post-operative inflammatory changes.
Case 5
Case 5 (Image 2)
Axial images demonstrate intense circumferential FDG uptake involving the gallbladder. A large gallstone is present. In such cases, ultrasound is recommended to exclude acute cholecystitis (the diagnosis was confirmed by ultrasound and at surgery). Interestingly, ultrasound frequently demonstrates no sonographic evidence of acute cholecystitis in these cases.
Case 6
Case 6 (Image 2)
Axial images demonstrate intense circumferential gallbladder wall uptake. CT images reveal no definitive abnormality. Ultrasound was recommended, which was suspicious for acalculous cholecystitis (confirmed at surgery).
Case 7
Case 7 (Image 2)
Coronal fused image demonstrates the MIP finding to represent gallbladder wall uptake, raising a suspicion for cholecystitis.
Case 7 (Image 3)
Axial images demonstrate intense gallbladder wall uptake and cholelithiasis. In this image, the uptake and wall thickening (arrows) are asymmetric. Surgical pathology revealed acute cholecystitis and an incidental gallbladder cancer (cancer is seen in ≈ 2% of routine cholecystectomy specimens).
Case 8
Case 8 (Image 2)
Coronal fused image demonstrates the MIP finding to represent focal uptake involving the gallbladder.
Case 8 (Image 3)
Axial images confirm the focal nature of this uptake, corresponding to what could be soft tissue (poorly evaluated on CT due to the contracted state of the gallbladder). Ultrasound revealed a polypoid mass, confirmed to be malignancy at surgery. Caveat: Focal uptake should always raise a suspicion of malignancy.
Case 9
Case 9 (Image 2)
Axial fused image demonstrates extensive metabolic activity along the periphery of the gallbladder.
Case 9 (Image 3)
Axial fused image (just inferior to Image 2) demonstrates marked gallbladder wall thickening, intensely avid. In this case, the etiology is also apparent: a hypermetabolic primary pancreatic cancer (circle), causing seeding (carcinomatosis) along the periphery of the gallbladder.
Case 10
Case 10 (Image 2)
Axial images reveal intense gallbladder uptake. Calcification is present, suggesting cholelithiasis. The contracted state of the gallbladder (secondary to oral contrast administration) significantly limits its evaluation. Given the very intense uptake, ultrasound was recommended. Cholelithiasis and a polypoid mass were noted. At surgery, gallstones and a gallbladder cancer were present.
Case 11
Case 11 (Image 2)
Ill-defined intense uptake is noted to involve the liver (subtle associated hypodensity may be present on the CT images, poorly evaluated without intravenous contrast), most consistent with hepatic metastatic disease.
Case 11 (Image 3)
An enlarged FDG-avid periportal lymph node is present, most consistent with metastatic adenopathy. The patient’s hepatic metastasis is also again noted.
Case 11 (Image 4)
An intensely FDG-avid lytic sacral metastasis is present.
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