Imaging modalities useful for the diagnosis of VM include ultrasonography, MRI, and venography. MRI is the most informative.

If the diagnosis cannot be made by history and physical exam, or to define the extent of a VM prior to sclerotherapy or excision, MRI is the imaging study of choice.

The complications of VM, like all vascular anomalies, depend on the extent and location of the lesion. Lesions located on the head or neck may cause progressive distortion, malalignment, or airway compromise. VM of the extremity may lead to leg-length discrepancy, pathologic fracture, and hemarthrosis causing degenerative arthritis. Gastrointestinal VMs can cause bleeding and chronic anemia. Lesions of the gastrointestinal tract may be located from the esophagus to the anus.

The gastrointestinal lesions are distributed throughout the gastrointestinal tract, and can cause intussusception, volvulus, and most commonly, gastrointestinal bleeding.

Stagnation within a large VM results in a localized intravascular coagulopathy. Thus a coagulation profile should be obtained in patients with extensive lesions or who have a history of easy bruising.

No known systemic pharmacologic agents induced evolution of vascular malformations, and therefore they are not used for VMs.

Conservative treatment for symptomatic VM includes low-dose aspirin to minimize painful phlebothromboses and support stockings for extremity VM. Like LM, the mainstays of treatment for VM causing disfigurement, pain, or functional problems is sclerotherapy and surgical resection. Sclerosing agents include doxycycline, 100% ethanol, sodium tetradecyl sulfate, and OK-432 (killed group A S. pyogenes). As with LM, VM tends to recur after sclerotherapy because of recanalization. As a result, multiple injections are often required. Local complications of sclerotherapy include skin necrosis or local nerve damage. Systemic complications include hemolysis, sudden pulmonary hypertension, and cardiac and renal toxicities.

Although small, well-localized lesions may be excised primarily, larger lesions should be reduced by sclerotherapy prior to excision. Large, soft-tissue VM often requires staged excision. Gastrointestinal lesions causing anemia may be excised or sclerosed endoscopically. Multifocal bowel lesions of the blue rubber bleb nevus syndrome may be individually resected, although hundreds of lesions may be found and operative procedures may be extremely lengthy. Bowel resections should be performed only in areas with a high density of VM. Otherwise, multiple enterotomies can be made to remove lesions through a single enterotomy site by intussusception of adjacent bowel. Colorectal lesions may be controlled by sclerotherapy. If this fails, colectomy, mucosectomy, and pull-through may be performed.