Management
The decision to treat a VM is dependent on location of the lesion, extension into adjacent tissue, presence of pain, functional impairment, or aesthetic appearance. Small, focal VMs which are not causing pain or functional impairment are often treated conservatively with observation alone. Compression garments improve vascular flow and reduce stasis, and help with pain. Custom compression garments are recommended to ensure proper fit and comfort, with typical pressures of 20-40 mmHg (23,24). Compression should always be encouraged in VMs, as it can help prevent or slow the development of venous ectasia. Analgesics may be used for mild to moderate pain.
This patient had a small, focal, symptomatic VM which is amenable to sclerotherapy. Multiple rounds of sclerotherapy may be needed depending on lesion size and clinical symptoms. In this procedure, sclerosing agents are percutaneously injected into the VM. Sclerotherapy can be used alone for symptomatic relief, or in a staged approach in which pre-operative sclerotherapy is performed to improve success of subsequent excisional or debulking surgeries (25). The efficacy of sclerotherapy is generally related to the sclerosing agent and dwell time within the VM. Choice of sclerosing agent is dependent on a number of different factors, including VM location (depth, and proximity to adjacent structures), as well as ability to control venous drainage (26,27). If robust venous drainage is present, occlusion of outflow veins is needed prior to injection of the sclerosing agent to prevent it from flowing out of the VM without proper endothelial contact time. Occlusion of venous drainage can be accomplished by use of a tourniquet, or by embolizing the outflow vein(s) with liquid embolic agents, coils or plugs (28). Table 1 lists a selection of commonly used sclerosing agents, their mechanism of action, and potential side effects. Given the superficial nature of the lesion described above, bleomycin or sodium tetradecyl sulfate (STS) would be acceptable choices. Alcohol should be avoided for lesions near nerves, superficial lesions, or VMs involving the mucosa given risk for inflammation, edema and necrosis which may affect nearby structures and damage surrounding tissues (29,30). This patient had a positive response to sclerotherapy, with decreased swelling and minimal pain six months after treatment (Fig 3).
Surgical intervention can be considered in patients with symptomatic VMs if excision with appropriate margins does not injure vital structures. This approach may be appropriate for lesions which are not amenable to sclerotherapy. Depending on the extent of the lesion, surgery may or may not be curative, as VMs are prone to regrow if vascular tissue remains after surgery (35,36). A surgical approach should focus on a defined anatomical area, preservation of critical neurovascular structures, and minimizing blood loss by staged approaches if needed (37).
While not applicable to this case as the patient had a localized VM amenable to sclerotherapy, patients with larger VMs not responsive to sclerotherapy or non-surgical candidates can consider the use of sirolimus. Sirolimus is an oral mammalian target of rapamycin (mTOR) inhibitor, which has been shown to be highly effective in patients with a wide variety of vascular anomalies. In patients with VM, multiple studies have described a benefit in reduction of lesion size and pain symptoms with the use of sirolimus (38). Sirolimus is generally dosed at 0.8 mg/m2 per dose every 12 hours, with monitoring of trough levels for dose adjustment. Target trough levels depend on lesion type, and the balance between treatment benefit and the potential for side effects. Potential side effects of sirolimus therapy include mucositis, count suppression, hypercholesterolemia, and increased liver enzymes. These side effects are reversible with either dose reduction or cessation of therapy (39). Patients receiving sirolimus are advised to seek medical attention with fevers and are prescribed prophylaxis against pneumocystis jiroveci pneumonia (PJP).