Capillary malformation−arteriovenous malformation syndrome: a multicentre study

Summary Background Capillary malformation–arteriovenous malformation (CM‐AVM) syndrome is a rare syndrome with characteristic skin lesions that are associated with fast‐flow vascular malformations (FFVMs) in one‐third of patients. Few case series have been described, and none in Spain. Aim To identify the prevalence of dermatological parameters, FFVMs and associated features in a large series of patients with CM‐AVM. Methods We conducted an observational study of patients with CM‐AVM syndrome diagnosed in 15 Spanish hospitals over 3 years. The main clinical, radiological, genetic findings and associated diseases were analysed. Results In total, 64 patients were assessed. In 26.5% of cases, the diagnosis was incidental. In 75% of patients, there was one significantly larger macule, which we termed the ‘herald patch’. FFVMs were detected in 34% of the patients, with 30% located on the skin, 7.8% in the brain and in 1.5% in the spine. There was a positive family history in 65% of the 64 patients. Genetic analysis was performed for RASA1 mutations in 57 patients, of whom 42 (73%) had a positive result. All 4 patients tested for EPHB4 mutations had a positive result. No tumour lesions were detected in the series, except for five infantile haemangiomas. Conclusions Our data on clinical lesions, associated FFVM, family history and genetics are similar to those previously published in the literature. An extensive data analysis failed to demonstrate any statistically significant association between the presence of an FFVM and any clinical, familial or genetic parameter that could predict its onset, although a link between the presence of a herald patch on the midline face and the presence of a brain FFVM was observed. We did not detect any genotype–phenotype correlation.