Characteristic CT and MRI findings of intracranial chondroma

Background: Intracranial chondromas are rare benign tumors. To date, few data are available on their neuroradiological features. Purpose: To describe a series of patients with intracranial chondroma and to analyze and discuss the computed tomography (CT) and magnetic resonance imaging (MRI) features that may distinguish chondromas from other intracranial neoplasms. Material and Methods: We retrospectively analyzed clinical and medical imaging data of six patients who had pathologically confirmed intracranial chondromas in our two institutions between July 2006 and September 2011. Both CT and MRI scanning were performed in all six cases. Results: Five tumors were located at the skull base and one originated from the falx. CT images revealed well-demarcated, irregular lobulated and variable density masses with obvious calcification (6/6), no or slight enhancement, without peritumoral edema, and frequently accompanied by erosion and destruction of surrounding bone (5/6). Tumor parenchyma appeared heterogeneously hypointense on T1WI, and hyperintense or mixed hyperintense and hypointense on T2WI, while the calcification appeared hypointense on T1WI and T2WI in five cases, demonstrating significant inhomogeneous enhancement on postcontrast MRI, which revealed the typical "punica granatum seeds" sign. Only one case showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, and relatively uniform obvious enhancement on postcontrast scans. Conclusion: These characteristic CT and MR findings, combined with the location of the lesions and the history of a long duration of clinical symptoms, may prove helpful in differentiating intracranial chondromas from other more common tumors.