= HPC = ANGIOBLASTIC MENINGIOMA

= rare neoplasm thought to arise from Zimmermann pericytes surrounding capillaries + postcapillary venules

Incidence:<0.4% of all CNS tumors

Age: 38–42 years (younger age group than for meningiomas); M÷F = 1.4÷1

Path: part of spectrum with solitary fibrous tumor; WHO grade II / grade III lesion

Histo: closely packed randomly oriented cells with scant cytoplasm + interrupted by gaping capillary-caliber vessels with a branching “staghorn” pattern; CD34 positive; EMA negative

Location: supratentorial; almost always solitary

• headache, seizure, visual dysfunction, motor weakness
• similar to meningioma
• narrow base of attachment to dura
• significant edema in subjacent brain parenchyma (frequent)

Angio:

• hypervascular lesion with dual blood supply from ECA + ICA / vertebral artery
• NO early draining veins
• fluffy” stain (rather than “sunburst” stain of meningioma)

MR:

• typically isointense to gray matter on both T1WI + T2WI
• ± prominent flow voids
• avid enhancement, sometimes heterogeneously
• “mushrooming” into adjacent brain
• lobulated / irregular borders
• high myo-inositol peak at 3.56 ppm + lack of alanine

DDx: meningioma (broad base of dural attachment, sunburst” stain of tumor blush, low myo-inositol + positive alanine peak)