Angiographic Evidence of a Purely Pial Bihemispheric Intracranial Hemangiopericytoma

Abstract

Background. Classification of hemangiopericytoma (HPC) has evolved to a mesenchymal, nonmeningothelial grade two or three neoplasm according to the World Health Organization; however its blood supply has always been defined by dual origin, pial and dural contribution. Case Description. We present the case of a patient with an intracranial HPC with only pial vascular supply. Angiography confirmed the lack of dural supply to this bihemispheric intracranial mass. Subsequent histologic examination confirmed the diagnosis of hemangiopericytoma. Angiographic evidence here is atypical of the natural history of hemangiopericytomas with dual vascular supply and was critical in the decision-making towards surgical resection without tumor embolization. Conclusion. Data presented suggests the lack of dural vascular supply alone does not rule out the diagnosis of hemangiopericytoma.

Figure 1

Axial, noncontrast CT scan (a) demonstrating a hyperdense, bifrontal, parasagittal lesion with surrounding vasogenic edema. T1 weighted, postcontrast MRI images showing (b) axial, (c) sagittal, and (d) coronal views of the mass.

Figure 2

Cerebral angiogram in (a) AP and (b) lateral common carotid injections demonstrating blood supply of the tumor crossing midline from the left distal ACA. The left carotid venous phase (c) shows a dense tumor blush. An oblique right common carotid injection (d) demonstrates no contribution to the tumor.

Figure 3

Photomicrograph of tissue sections showing papillary and clear cell morphology with hypervascularity, but no characteristic staghorn appearance (a). Necrosis, intratumoral hemorrhage, nuclear atypia, and frequent mitotic figures were seen (b) and there was patchy and strong CD34 staining (c), as well as strong and diffuse CD99 staining (d).