INTRACRANICAL HEMANGIOPERICYTOMA: CASE REPORT AND REVIEW OF LITERATURE

PURPOSE: We present a case of intracranical hemangiopericytoma (HPC) in a patient with migraine (male, 49 years old), who also presented mental confusion and partial left sensorimotor syndrome. We will also provide some elements regarding the international classification of this rare and highly vascularized mesenchymal tumor, and will consider possible differential diagnosis with other more common extra-axial masses. METHODS: After a preliminary examination in ER, patient underwent to head CT examination and was then transferred to the neurosurgical unit. The day after a brain MR examination was performed using advanced techniques too (PWI, and MRS); before surgery also functional MR imaging (fMRI) and CTA where performed. RESULTS: CT scans showed a left frontoparietal expansive lesion, most likely of extra-axial nature, with heterogeneous characteristics and polilobulated margins. There was a severe mass effect on adjacent parenchymal structures and heavy involvement on the adjacent skull bone. MR examination with conventional sequences confirmed the extra-axial nature of the lesion, which appeared to be highly vascularized as later confirmed by CTA. The analysis of lesions perfusion by DSCE-PWI (EPI-T2*w) confirmed these findings, showing permeability curves compatible with a highly vascularized lesion (high rCBV and rCBF values) without hematoencephalic barrier. Spectroscopy examination showed an increased Cho peak, compatible with a high cell proliferation with a lipid/lactate peak into the intralesional areas of necrosis. Diagnostic hypothesis of HPC was placed. The fMRI presurgical examination allowed to identify language and motor areas that were all considerably dislocated. CONCLUSIONS: Pathologic examination confirmed diagnosis of anaplastic HPC (WHO III), a tumor originating from malignant transformation of microcircle Zimmerman’s pericytes, a rare tumor of the central nervous system (0,4% of all primary tumors, previously classified as angioblastic meningioma). Anaplastic HPS (AHPC) is usually characterized by a more lobulated shape, substantial bleeding, necrosis or cystic areas, marked peritumoral edema and signs of cranial table erosion, while the typical “dural tail” sign is more frequent in the non-anaplastic types (WHO II).