Bifocal Tibial Kaposiform Hemangioendothelioma Responsive to Vincristine Therapy: A Case Report

BACKGROUND Kaposiform hemangioendothelioma is a rare locally aggressive vascular endothelial-derived spindle cells neoplasm. Herein, we report a rare case of bifocal tibial kaposiform hemangioendothelioma. CASE REPORT A 9-year-old female presented with a 2-year history of pain and swelling in the left leg. The patient had a high plasma level of the D-dimer and fibrinogen. Radiography revealed a centric lytic lesion on the left proximal tibial metaphysis and an eccentric lateral distal tibial metaphyseal. Histopathologic examination of the sample taken from the distal tibia revealed a dense spindle cell tumor with lobular architecture composed of compact spindle cells compressing small slit-like vascular spaces, forming glomeruloid nests. No necrosis was identified. Based on these findings and the positive immunohistochemical staining for CD31, CD34, and D2-40, the patient was diagnosed with kaposiform hemangioendothelioma. Treatment was started by using vincristine chemotherapy, after which the patient developed temporary peroneal neuropathy, which improved over the next 3 months. CONCLUSIONS Bifocal tibial kaposiform hemangioendothelioma lesions are unique in pediatric patients and can be successfully treated with vincristine chemotherapy. In these cases, the treating physician should be aware of peroneal neuropathy as a potential complication of vincristine administration.