PET-CT

Fibroblast activation protein, alpha

Computed tomography

Fibrosis

Urology

Cancer research

Biochemistry

Retroperitoneal space

Radiology

Hydronephrosis

Immunology

Avidity

Retroperitoneal fibrosis

In vitro

Internal medicine

Medicine

Chemistry

Nuclear medicine

Fibroblast

Urinary system

Antibody

Cancer

Positron emission tomography

Pathology

Clinical Nuclear Medicine

A 26-year-old man presented with a retroperitoneal mass with left urinary tract obstruction and hydronephrosis recently. 18 F-FDG PET/CT showed the retroperitoneal mass had intense and homogeneous FDG avidity. In 68 Ga-FAPI PET/CT, the retroperitoneal mass showed intense radioactivity without other organ involvements. The patient was finally diagnosed with idiopathic retroperitoneal fibrosis. After treatment, the follow-up CT showed significant decrease in size of the retroperitoneal mass. The current case indicated that idiopathic retroperitoneal fibrosis had active uptake of 68 Ga-FAPI.

Idiopathic Retroperitoneal Fibrosis With Intense Uptake of 68Ga-Fibroblast Activation Protein Inhibitor and 18F-FDG