F-18 FDG-PET/CT in aseptic abscesses with recurrent febrile abdominal pain.

Objective: Mendelian and complex autoinflammatory disorders frequently manifest as recurrent abdominal pain and fever. Diagnosis may be difficult and scant data are available about the interest of 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in such conditions, particularly aseptic abscesses (AA).

Material And Methods: We analyzed five cases of AA in which FDG-PET/CT was performed at diagnosis (n = 2) and after a suspected relapse (n = 5). Follow-up FDG-PET/CT was performed in two patients 9 days and 6 weeks after the initiation of oral corticosteroids.

Results: FDG-PET/CT showed intense uptake foci in the abdominal lymph nodes (n = 4), liver (n = 2) and spleen (n = 4) before treatment. A marked metabolic response was observed while patients were being treated. In a relapsing patient with abdominal pain but no raised CRP, although CT scan was unchanged, abnormal uptake of FDG was observed. By contrast, some lesions previously observed on CT scan displayed no fixation on new FDG-PET/CT and were suggestive of sequelae in three patients.

Conclusion: Although nonspecific, FDG-PET/CT may be an interesting tool for the diagnosis and management of recurrent and febrile abdominal pain in AA. At the time of relapse, it can differentiate between a sequela of previous flares and a new localization. It can be used for whole-body screening to look for other asymptomatic disease localizations.