The aim of the BEST study is to examine the feasibility of assessing patient and clinician reported outcome of a single electrosclerotherapy treatment of vascular malformations.

• Sclerotherapy = injection of Bleomycin into vascular birthmarks to seal off abnormal vascular channels
• Electroporation = application of an electric field to vessels treated with a handheld needle electrode
• Electrosclerotherapy = a combination of Bleomycin sclerotherapy and electroporation

Inclusion Criteria:

• New patients presenting with a vascular malformation suitable for Bleomycin sclerotherapy treatment
• Existing patients presenting with a poor response to treatment, performed more than 6 months ago
• Placement of a needle electrode into the vascular malformation is technically possible
• Evaluation of response to treatment is possible on photo documentation
• Patients agreeing to participate in the study
• The ability to understand written and spoken English

Exclusion Criteria:

• Patients not agreeing to participate in the study
• Pregnancy
• Breastfeeding
• Previous high systemic Bleomycin exposure (more than 3000 IU)
• Patients unable to provide written, informed consent
• Patients in which needle electrode placement is not possible
• Response to treatment not evaluable by photo documentation
• Patients unable to speak English