Surface-based chondroblastoma of the tibia: a unique presentation.

Abstract

Chondroblastoma is a benign tumor classically located within the epiphysis of the long bones. The tumor is believed to arise from immature cells of the epiphyseal plate. Purely metaphyseal or diaphyseal chondroblastoma is exceedingly uncommon, occurring in approximately 2% of chondroblastoma cases. In all of these non-epiphyseal-based cases, the tumor has been intramedullary. We describe the histologic and imaging features of the first detailed description of a surface-based chondroblastoma. The tumor was located in the anteromedial midshaft of the tibia in a 47-year-old male. We discuss the diagnostic considerations and possible etiology of chondroblastoma given this unusual location.