A case of chondromesenchymal hamartoma of the skull base

Here, we present an unusual case of chondromesenchymal hamartoma limited to the skull base without sinonasal involvement. A 19-year-old man presented with a two-month history of diplopia and right abducens palsy. Imaging revealed a clival mass extending into the right cavernous sinus with central and peripheral calcifications, marked T2 hyperintensity, no restricted diffusion, and a heterogeneous and predominantly peripheral enhancement. Endoscopic endonasal resection was performed, and histopathological examination confirmed a chondromesenchymal hamartoma. The imaging features of chondromesenchymal hamartomas are similar to those of chondrosarcomas, making differentiation difficult. Although germline or somatic DICER1 testing was not performed in our case, the detection of DICER1 gene mutations may help establish a diagnosis.