1.3 Kaposiform Lymphangiomatosis
Kaposiform lymphangiomatosis (KLA) is an aggressive lymphatic anomaly
that is associated with significant morbidity and high mortality. KLA
most commonly involves the thoracic cavity, bone and spleen [7].
Clinical presentation is typically severe, particularly at a young age,
and progression occurs without treatment. Complications include organ
compromise, pleural and pericardial effusions, ascites, pain, and
functional issues. KLA is associated with a life-threatening
coagulopathy characterized by severe hypofibrinogenemia,
thrombocytopenia and bleeding [8]. Effusions and ascites are often
hemorrhagic. Defining histopathological features are abnormal lymphatic
channels with focal areas of spindle-shaped “kaposiform” endothelial
cells, positive for D2-40 and PROX-1 [7]. Platelet trapping is also
seen in KLA, suggesting that the pathogenesis of the coagulopathy is
similar to Kasabach-Merritt phenomenon (KMP) occurring in kaposiform
hemangioendothelioma (KHE) and tufted angioma (TA) [9]. Recently,
RAS mutations were identified in affected tissue of patients with KLA
[10].