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).