Not All That Glows Is Cancer: Ga-68 FAPI PET/CT Uptake in Eosinophilic Esophagitis

Area of Science:

• Gastroenterology
• Nuclear Medicine
• Oncology

Background:

• Eosinophilic esophagitis (EoE) is an immune-mediated esophageal disease.
• FAPI PET/CT is a novel imaging technique for fibroblast activation, often used in oncology.
• Distinguishing EoE from esophageal malignancy can be challenging.

Purpose of the Study:

• To report a case of eosinophilic esophagitis with intense Ga-68 FAPI PET/CT uptake mimicking malignancy.
• To highlight the potential for false-positive findings with Ga-68 FAPI PET/CT in inflammatory conditions.
• To emphasize the importance of multimodal diagnostic correlation.

Main Methods:

• Case report of a 70-year-old male with dysphagia.
• Endoscopy with biopsy, F-18 FDG PET/CT, and Ga-68 FAPI PET/CT.
• Peripheral blood eosinophil count and repeat biopsy for diagnosis.

Main Results:

• Initial biopsy negative for malignancy.
• F-18 FDG PET/CT showed low-grade uptake; Ga-68 FAPI PET/CT demonstrated intense, diffuse esophageal uptake.
• Repeat biopsy confirmed eosinophilic esophagitis with peripheral eosinophilia.

Conclusions:

• Ga-68 FAPI PET/CT can yield false-positive results in eosinophilic esophagitis, mimicking malignancy.
• Multimodal correlation including clinical, endoscopic, and histopathological findings is essential.
• Careful interpretation is needed to avoid misdiagnosis in esophageal diseases.