Hepatic Eosinophilic Granuloma Mimicking Liver Metastases of Unknown Primary Focus on 18 F-FDG and 68 Ga-FAPI PET/CT

Area of Science:

• Hepatology
• Radiology
• Pathology

Background:

• Hepatic eosinophilic granuloma (HEG) is an uncommon benign liver condition.
• Distinguishing HEG from malignant liver lesions can be challenging due to overlapping imaging features.

Purpose of the Study:

• To report a case of HEG presenting with imaging findings mimicking liver metastases.
• To highlight the diagnostic challenges and the importance of histopathological confirmation.

Main Methods:

• A 53-year-old male patient with persistent right upper abdominal pain.
• Magnetic Resonance (MR) imaging revealing multiple liver nodules with irregular enhancement.
• Positron Emission Tomography (PET) using 18F-FDG and 68Ga-FAPI showing elevated tracer uptake.
• Ultrasound-guided liver biopsy for definitive diagnosis.

Main Results:

• MR imaging demonstrated multiple liver nodules suspicious for malignancy.
• 18F-FDG and 68Ga-FAPI PET scans indicated high tracer uptake, further suggesting metastatic disease.
• Histopathological examination of the biopsy specimen confirmed hepatic eosinophilic granuloma.

Conclusions:

• Hepatic eosinophilic granuloma can present with imaging characteristics that mimic liver metastases.
• Advanced imaging modalities like PET/CT may not always differentiate HEG from malignancy.
• Ultrasound-guided biopsy remains crucial for the accurate diagnosis of hepatic eosinophilic granuloma.