Atypical chondroblastoma of the distal femur with exophytic mass: A rare presentation and diagnostic dilemma

Chondroblastoma is a benign epiphyseal chondromatous lesion typically seen as a small, well-defined, eccentric epiphyseal lesion with thin rim of surrounding bone sclerosis. Soft tissue extension, metaphyseal involvement, periosteal reaction, cortex breach though not pathognomonic, are reported in literature. We present a case report of a patient with chondroblastoma showing atypical radiological presentation with exophytic mass in order to give reader a perspective on atypical radiological features and corroborating these finding intraoperatively and on histopathology.
 

Keywords: Exophytic mass, Atypical bone tumour, Benign bone tumour.