Single-center experience with sirolimus therapy for vascular malformations

Vascular malformations (VMs) are described as congenital malformations of the vasculature derived from capillaries, veins, lymphatic vessels, arteries, or a combination of these vessels. They can cause significant morbidity resulting from soft tissue hypertrophy-related disfiguration, bony abnormalities, and even organ compromise. They are usually treated with various interventional procedures to achieve local control; however, the chance of success decreases as the anatomical distribution of the malformation widens. Unfortunately, medical treatment options have been quite limited in these patients. Sirolimus is an antiangiogenetic and antiproliferative pharmacologic agent that has been used for the management of VM in the last decade. We report 6 pediatric patients (4 with capillary lymphaticovenous malformations, 1 with lymphaticovenous malformation, and 1 with venous malformation) seen at our clinic within the last 2 years with lesions covering wide anatomical areas. After the patients had unsuccessfully undergone various treatments at various centers, they were treated at our facility with peroral sirolimus. The mean duration of treatment was 13 months, but in 3 patients, tapered dosing continues. Five patients achieved partial responses. The response to sirolimus treatment increased as the lymphatic component of the VM increased. All patients tolerated sirolimus well; side effects were acceptable. Sirolimus is a safe and effective medical treatment for widely distributed VMs with significant lymphatic components and no further local treatment option.