Long-term staged management of an extensive pelvic and right lower-extremity vascular malformation with major venous abnormalities and postprocedural pulmonary embolism: A case report

Extensive vascular malformations involving a limb and major named veins may require repeated treatment over many years. Their abnormal venous anatomy may remain clinically important even when local symptoms are controlled, particularly when subsequent interventions are planned. We report the long-term course of a 26-year-old man with a congenital vascular malformation involving the pelvis and right lower extremity, diagnosed at 13 years of age and historically described as an arteriovenous malformation. Historical CT angiography reports described arteriovenous components together with extensive venous abnormalities, including aneurysmal dilatation of the right popliteal and external iliac veins. Staged surgery during adolescence was followed by an approximately 13-year interval without further invasive treatment, during which the patient initially remained clinically stable before gradually developing recurrent symptoms. At 26 years of age, progressive symptoms prompted combined endovenous laser treatment, electrocoagulation, and sclerotherapy. On postoperative day 7, the patient developed occlusive right popliteal venous thrombosis and acute bilateral pulmonary embolism requiring systemic thrombolysis followed by anticoagulation. The patient stabilized after treatment. At approximately 3-month cardiology follow-up, he was asymptomatic, with preserved cardiac function and good exercise tolerance. Longer-term symptom control was maintained with class III compression therapy, therapeutic exercise, and regular physical activity, with improvement in pain and lower-extremity edema. This case illustrates that major venous abnormalities may remain clinically relevant throughout the long-term course of a complex vascular malformation. In patients undergoing further intervention, lesion-specific venous anatomy and pre-existing thrombotic changes within malformed venous spaces should be considered alongside conventional peri-procedural thromboembolic risk factors. Long-term management should remain individualized and focused on symptoms, function, and surveillance of major vascular abnormalities.