Multicystic oligodendroglioma with calvarial destruction

Atypical meningeal hemangiopericytoma presenting with punched-out calvarial erosion

Meningeal hemangiopericytoma (HPC) is an infrequent but distinct entity affecting the craniospinal axis. A previously healthy 48-year-old man sustained a gradually progressing motor weakness in the left lower extremity. CT showed a hyperdense mass in the right frontal lobe. On MRI, it was 29 × 30 × 36 mm in dimension, appeared isointense on T1 and hyperintense on T2, and was intensely enhanced with erosive changes in the inner table adjacent to the tumor. The patient underwent tumor resection. Reflection of the bone flap revealed a punched-out erosion in the inner table with a defect of the dura over the upper part of the tumor. Microscopic findings were consistent with grade III HPC with dural invasion. A punched-out calvarial erosion and dural defect caused by an extra-axial tumor may be a high-grade HPC that requires extensive surgical resection.

Magnetic resonance imaging and computed tomographic characteristics of a glioma causing calvarial erosion in a dog

An 8-year-old female Boxer was examined for acute onset of seizures. On magnetic resonance imaging (MRI), an intra-axial mass with imaging features consistent with glioma was observed in the right cerebral hemisphere. A defect in the temporal bone adjacent to the mass was observed. Postmortem computed tomography (CT) confirmed temporal bone osteolysis and necropsy demonstrated a glioblastoma with associated calvarial erosion. Although occasionally described in human medicine, to our knowledge, this is the first description of a brain glioma causing calvarial erosion in a dog. Glioma should be included as a differential diagnosis for intracranial lesions that could cause bony changes in the skull.