Custom Mega Prosthesis in a Rare case of Epithelioid Hemangioendothelioma of Proximal Tibia – A Case Report

INTRODUCTION: Lytic lesions of the proximal tibia include a plethora of differential diagnoses. The most common ones are the Giant cell tumor, fibrous dysplasia, adamantinoma, chondromyxoid fibroma, and osteoblastoma. The rarer ones include vascular tumors such as hemangioma and hemangioendothelioma. A systematic line of investigations is essential to pick up the right diagnosis especially in case of rarer conditions. In this background, we present a case of lytic lesion of the proximal tibia which turned out to be epitheloid hemangioendothelioma (EHE). CASE REPORT: A 37-year-old female presented with pain and swelling in the left knee for 2 years. On examination, the patient had a 3 × 4 cm firm, non-tender, and well-defined swelling on the anterolateral aspect of the proximal tibia. X-ray showed a lytic lesion of the proximal tibia. Magnetic resonance imaging was suggestive of a giant cell tumor. However, the biopsy revealed a rare diagnosis of epithelioid hemangioendothelioma. CONCLUSION: The patient was managed with wide excision. In a young adult, arthrodesis may not be the best option; hence, we reconstructed the joint with a custom mega prosthesis (CMP). At 3 years follow-up, our patient had no signs of recurrence. To our best knowledge, this is the first report on the use of CMP in a case of EHE