Kaposiform hemangioendothelioma may have areas resembling juvenile capillary hemangioma. Unlike capillary hemangioma which is made up of discrete lobules of small vessels, this tumor consists of irregular rambling nodules. In addition, capillary hemangioma is positive for GLUT-1 which is negative in kaposiform hemangioendothelioma. Unfortunately, this marker was not available and it couldn’t be studied by immunohistochemistry. In kaposiform hemangioendothelioma, there are areas composed of spindle cells with slitlike vascular spaces resembling Kaposi sarcoma. As in the present case, the endothelial cells are typically positive for vascular markers such as CD31 and CD34 and vascular endothelial growth factor receptor 3, but only weakly positive for factor VIII-associated antigen.10
This pattern is similar to the antigen-expression profile of Kaposi sarcoma. To exclude Kaposi sarcoma, IHC staining for human herpes virus 8 is helpful,11
but this marker was not available. Although both entities (kaposiform hemangioendothelioma and Kaposi sarcoma) have spindle cells with slit-like lumina, hyaline globules, hemosiderin deposition and endothelial antigen expression, kaposiform hemangioendothelioma has also areas of epithelioid endothelium often in glomeruloid nests.10
In addition, high mitotic rate and nuclear atypia are not features of kaposiform hemangioendothelioma. In this case, nuclear atypia was minimal and mitosis was inconspicuous. Moreover, aside from the lymphadenopathic form seen in Africa, Kaposi sarcoma is rarely seen in children.
Lyons et al followed 22 patients with kaposiform hemangioendothelioma (age ranging from 8 months to 15 years; mean 2 years). Three of them died of disease, 8 were alive with disease, and 10 were alive without residual disease. Two patients developed regional perinodal soft tissue involvement, but distant metastasis didn’t happen in any.4
Their study emphasized that mortality is due to Kasabach-Merritt syndrome and not metastasic disease. Therefore, this tumor is continued to be classified as a vascular tumor of intermediate malignancy.3
The infant didn′t receive vincristine and his life threatening thrombocytopenia was uncontrollable without surgery. Other treatments such as arterial embolization of the mass were not possible because MR angiography was not available in the medical center. Irradiation has no role in this lesion at this age. Following surgery, the infant was discharged in good condition. He was still in good condition 1 year after surgery and showed no evidence of recurrence or complications related to the surgery.