Hepatic Metastasis From Duodenal Ampullary Carcinoma With Intense FAP Activity But Without FDG Uptake

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Ampullary carcinoma is a rare malignancy with a propensity for metastasis.
• Accurate detection of liver metastases is crucial for treatment planning and prognosis.
• Standard imaging modalities can sometimes be limited in detecting small or subtle metastatic lesions.

Purpose of the Study:

• To compare the diagnostic efficacy of 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT in identifying hepatic lesions suspicious for metastasis in a patient with a history of duodenal ampullary carcinoma.
• To evaluate the sensitivity and contrast of 68Ga-FAPI-04 PET/CT compared to 18F-FDG PET/CT in this specific clinical context.

Main Methods:

• A patient with a history of duodenal ampullary carcinoma and a suspicious liver lesion on CT was enrolled in a clinical trial.
• Both 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT were performed for comparative analysis.
• Final histopathology was obtained to confirm the nature of the hepatic lesion.

Main Results:

• 18F-FDG PET/CT showed no significant tracer uptake in the suspicious liver lesion.
• 68Ga-FAPI-04 PET/CT demonstrated high tracer uptake in the S7 liver segment, indicating high tumor burden.
• The tumor-to-background contrast was significantly more prominent on 68Ga-FAPI-04 PET/CT compared to 18F-FDG PET/CT.
• Histopathology confirmed the lesion as an infiltrating adenocarcinoma, consistent with metastasis from the primary duodenal ampullary carcinoma.

Conclusions:

• 68Ga-FAPI-04 PET/CT is a highly sensitive imaging technique for detecting liver metastases from duodenal ampullary carcinoma.
• 68Ga-FAPI-04 PET/CT offers superior tumor-to-background contrast compared to 18F-FDG PET/CT in this patient population.
• This finding suggests a potential role for 68Ga-FAPI-04 PET/CT in the surveillance and management of patients with a history of ampullary carcinoma.