Differential diagnosis of coagulopathy in vascular anomalies
It is important to be certain of the diagnosis as clinically the differential diagnosis of a vascular lesion with coagulopathy may overlap with other conditions (Table 1). Kaposiform lymphangiomatosis (KLA) is a very rare lymphatic disorder that usually presents with multifocal or diffuse involvement of the mediastinum, lungs, bones and abdomen. These patients can have very severe thrombocytopenia with coagulopathy similar to KMP18-20. They do not typically respond to corticosteroids. They can be differentiated from KHE by the presence of a somatic activating NRAS mutation which have not been shown in KHE21. Both KLA and KHE have elevation of angiopoetin-2 (Ang-2)22 but this may be a helpful biomarker to distinguish from other vascular lesions. Another vascular disorder that may present with bleeding and thrombocytopenia is multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT). MLT, however, does not usually have the findings of intravascular coagulopathy (hypofibrinogenemia, elevated d-dimer, prolonged PT/aPTT) and bleeding typically occurs directly from the lesions present in the gastrointestinal tract or lungs23,24. Some congenital hemangiomas may also present with a mild consumptive coagulopathy, but it is typically not as severe, and the congenital hemangiomas do not continue to enlarge after birth as the KHE with KMP typically do25. Large venous malformations may also have evidence of LIC presenting with very elevated d-dimer and, when severe, thrombocytopenia and hypofibrinogenemia26,27. These lesions should be differentiated from KHE with imaging findings.