Fibroadipose vascular anomaly successfully treated with sirolimus: experience in 3 children

Abstract

Abstract Purpose Fibro-adipose vascular anomaly (FAVA) is a unique lesion composed of dense fibro-fatty tissue and slow-flow vascular malformations and is associated with somatic PIK3CA mutations. The patient usually presents with pain, swelling, functional restriction, and skin hyperesthesia. Therapeutic armamentarium includes cryoablation, sirolimus, and surgical debulking/excision. Sirolimus is highly effective for treatment of FAVA and is well tolerated. Here, we report our experience of treating FAVA with sirolimus in 3 patients. Methods We retrospectively reviewed data of 3 patients with FAVA who were treated with sirolimus at our institution. Results A total of 3 patients with FAVA being managed with sirolimus were assessed. Two out of 3 were male. The ages of the patients were 2, 12, and 17 years respectively. Sirolimus was started at a dose of 0.8 mg/m2/dose two times a day, and patients were treated for a mean of 10.6 months (range 10–11 months). Dose adjustments were made to keep trough serum levels between 5 and 12 ng/ml. All of them had reduction in pain, and 1 of them experienced it within 4 days of therapy initiation. Follow-up MRI revealed reduction in size in all 3 patients. Sirolimus was well tolerated with mild acne and dyslipidaemia being the only side effects observed. Conclusion Sirolimus is quite an effective treatment for patients with FAVA and is well-tolerated without any major adverse effects. Given the rapid responses and a favourable safety profile, we believe that sirolimus can be considered for all patients with FAVA as a first-line therapy, but long-term follow-up data from well-designed clinical trials are required.