Fibro-adipose vascular anomaly (FAVA) - diagnosis, staging and management

The diagnosis and treatment of fibro-adipose vascular anomaly (FAVA) of the limb remains challenging since this entity is rare and complex. This paper is aimed to describe the clinical and imaging features, staging and management of this underrecognized disease of the limb.

Patients diagnosed with FAVA and managed between September 2019 and May 2022 in department of pediatric surgery & vascular anomalies of Xi'an international medical center hospital were retrospectively reviewed. Data extracted include age at presentation, previous diagnosis, affected muscles, symptoms, previous treatment, our management, and follow-up.

Thirty-two patients with FAVA were diagnosed and managed in our center. There was a female sex predominance, with 23 female (72%) and 9 male (28%) in the cohort. Only one lesion was noticed during infancy; the remaining presented at age 1 to 20 years (median, 7 years). The most commonly involved muscles were gastrocnemius (14/32, 44%) and soleus (13/32, 40%). Swelling (mass), pain and contractures were the most common presentations. MRI featured a heterogeneous and ill-defined intramuscular high signal intensity. Diseases were staged according to clinical features: stage I (pain stage, n = 4), stage II (contracture stage, n = 20) and stage III (deformity stage, n = 8). Patients with stage I disease underwent radical resection and obtained a cure. Patients with stage II disease received radical resection and possible Achilles lengthening, having an outcome of cure. Personalized treatment was required in patients with stage III disease, including radical/partial/staged resection, Achilles lengthening/tenotomy, joint capsulotomy, neurolysis/neurectomy, tendon transfer, stretching exercises, and oral sirolimus/alpelisib. Significant improvement of symptoms was achieved in most.

The most distinct features of FAVA include enlarging mass, severe pain and contracture. Based on distinct clinical and radiologic features, it is not difficult to make the diagnosis of FAVA. Earlier awareness of this disease can reduce misdiagnoses. Surgery-based comprehensive management can typically improve pain and contracture. Oral sirolimus or alpelisib plays an important role in treatment of unresectable lesions and major nerve involvement. Surgery alone can be curative in early stage FAVA.