Imaging strategy for focal nodular hyperplasia in children: long-term experience from two specialist European centres.

Background: Focal nodular hyperplasia (FNH) in children is a rare but benign tumour, which must be differentiated from malignant entities to avoid unnecessary treatment, leading to potential morbidity.

Objectives: To provide data on imaging findings of these lesions with a suggested algorithm for diagnosis, sampling and follow-up.

Materials And Methods: This retrospective review evaluated imaging of all patients diagnosed with FNH in two tertiary referral centres in Europe between 1975 and 2018.

Results: One hundred and four patients with 137 tumours were reviewed. The mean age at presentation was 8.2 years. The median tumour size was 5 cm (range: 0.3-29 cm). Multiple lesions were seen in 16.3% of patients. The male-to-female ratio was 1:2.

Conclusion: FNH with typical features on imaging can be safely followed up once the diagnosis has been established. The use of contrast-enhanced ultrasound and magnetic resonance imaging allows accurate characterisation in most cases. Histological sampling is only advised when there is diagnostic doubt. Atypical arterial enhancement of FNH should prompt the search for a congenital portosystemic shunt.