Extra-axial tumor with extension through the skull: atypical meningioma vs hemangiopericytoma
Presentation
Left posterior skull bulging.
Patient Data
Skull X-ray
Skull x-rays show a slight left parietal bone impression area and signs of periosteal reaction. A radiopaque nodular area along the right temporal bone is also noted.
CT Brain
CT study shows a hyperattenuating extra-axial mass at left parietal region with an important homogeneous enhancement and that invades and partially destroys the adjacent left skull parietal bone, reaching the subgaleal region. The mass has contact with the sagittal superior sinus without causing its thrombosis. Left parietal lobe is compressed by the mass and has a focal hypoattenuating area.
There is also a calcified extra-axial lesion on right middle fossa adjacent to the temporal bone (undetermined, calcified meningioma?)
Case Discussion
This case shows a extra-axial mass that invades the dura and the adjacent skull. The differential diagnosis must be considered between an atypical meningioma and a hemangiopericytoma.
Distinguishing an atypical meningioma from a hemangiopericytoma is difficult on imaging. When a large mass such as this invades bone, giving both as a differential is prudent.
Unfortunately there was no feedback of this patient's final diagnosis.