Kaposiform hemangioendothelioma.

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular neoplasm that mainly occurs during childhood. It generally originates on the skin, usually affecting deeper tissue by infiltrative growth. It appears as one or multiple masses, and in most cases is associated to consumptive coagulopathy (Kasabach-Merritt syndrome), and lymphangiomatosis. Although visceral involvement is very uncommon, several cases with bone, retroperitoneal, or mediastinal involvement have been described. These tumors tend to be locally invasive, but are not known to produce distant metastases. The development of KHE in adolescents or in adults is very rare, but cases have also been described. Several factors are associated with the outcome of patients with KHE: accessibility to surgical excision, location (cutaneous versus visceral), size of tumoral mass, clinical response to interferon and glucocorticoids, and the absence of lymphangiomatosis and Kasabach-Merritt syndrome, may result in partial remissions. On the other hand, bulk visceral masses lead to a 40-50% mortality rate, mainly due to progressive failure of the infiltrated organ(s), in spite of interferon, glucocorticoids, and combined chemotherapy. In conclusion, the onset of a consumptive coagulopathy following the presence of a vascular tumor, in children as well as in older patients, should spark suspicion of KHE, among other entities.