Abstract

Thrombosis is a known complication of vascular malformations possibly exacerbated by slow flow, hemostasis, and platelet sequestration. This can result in clot formation, consumption of coagulation factors, and, rarely, localized intravascular coagulation.  Thrombosis within the lymphatic system, however, is less common due to the inhibition of fibrin generation, as cells lack surface anionic phospholipids, low levels of coagulation factors, and enhanced fibrinolytic activity at baseline making lymphatic fluid hypo-coagulable.  Despite these protective factors, provoked lymphatic thrombosis is known to occur due to malignancy, infection, and iatrogenic procedures.  While previous studies have shown that cases of thrombosis in venous malformations have differing clinical presentations compared to those of combined venous and lymphatic malformations, the existing literature is unclear whether thrombosis may appear in lymphovascular malformations independent of other thromboembolism risk factors. A retrospective examination of pediatric lymphovascular cases at our institution revealed several cases demonstrating thrombosis in the lymphatic components of lymphovascular malformations in patients without other thromboembolism risk factors. We hypothesize this is due to the slow flow of lymph fluid secondary to malformation anatomy. Therefore, even though thrombotic processes originating in the lymphatic spaces are rare, one should not think this phenomenon only happens in vascular malformations and should not rule out the possibility of a lymphovascular pathologic process. This study highlights the need for heightened clinical awareness of thrombosis causes involving lymphatic channels. Increasing awareness and clinical suspicion of lymphovascular or solely lymphatic causes of thrombosis could improve diagnostic accuracy and treatment outcomes for patients experiencing thrombotic complications.