Teaching NeuroImage: Histopathologically Confirmed Intracranial Enchondroma/Low-Grade Chondrosarcoma and IDH1 -Mutated Diffuse Glioma in Ollier Disease

Abstract

A 3-year-old girl presented with leg deformities diagnosed as enchondromatosis (Ollier disease), which is a rare, sporadic, skeletal disorder characterized by hamartomatous growth of cartilage cells within metaphyses of long bones. In 2008, fluid-attenuated inversion recovery signal hyperintensity in her left frontal lobe (Figure, A) and skull-base enchondroma (Figure, B) were discovered. Her enchondromatosis required amputation of digits that were heavy and unusable (Figure, C and D). In 2017, surveillance imaging revealed enlargement of the frontal tumor, leading to craniotomy for a WHO grade 2 astrocytoma. Ollier disease is associated with IDH mutations1 and patients must be monitored for sarcomatous transformation of enchondromas and extraosseous malignancies including gliomas.2