PMC5055928_01
Axial (a) and coronal (b) noncontrast computed tomography (CT) of the head demonstrates hemorrhage in the region of the inferior right cerebellar peduncle, which appeared intraparenchymal, with extension into the fourth ventricle.
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A head computed tomography (CT) without contrast demonstrated hemorrhage in the region of the inferior right cerebellar peduncle, which appeared intraparenchymal, with extension into the fourth ventricle (Figure 1).
Axial (a) and coronal (b) CT angiography (CTA) of the head in the arterial phase demonstrates unchanged hemorrhage in the region inferior right cerebellar peduncle, likely intraparenchymal, with extension into the fourth ventricle without evidence of aneurysm or vascular malformation. The right posterior inferior cerebellar artery (PICA) is not well seen (arrow in (b) indicates the normal left PICA) and may be compressed by surrounding hemorrhage, involved with vasospasm or thrombosed.
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A head CT angiography (CTA) with contrast was then performed, which did not reveal an aneurysm or vascular malformation (Figure 2).
Axial T2-weighted (a) as well as axial (b) and coronal (c) T1-weighted contrast-enhanced magnetic resonance imaging (MRI) of the brain demonstrates an enhanced right cerebellopontine angle mass underlying the hemorrhage in the right cerebellopontine angle with central areas of nonenhancement. One year after resection, axial 3D T1-weighted contrast-enhanced MRI of the brain (d) demonstrates interval postsurgical changes of right retromastoid craniotomy for resection of the right cerebellopontine angle tumor without evidence of residual tumor.
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Magnetic resonance imaging (MRI) of the brain demonstrated an enhanced right cerebellopontine angle mass underlying the hemorrhage in the right cerebellopontine angle (Figures 3(b) and 3(c)). A cleft of T2 hyperintensity between the mass and the medulla representing cerebrospinal fluid established that the mass and hemorrhage were actually extra-axial (Figure 3(a)). Finally, brain MRI performed one year later demonstrated interval resection of the right cerebellopontine angle tumor without evidence of residual tumor (Figure 3(d)).
Hemangioma of the cerebellopontine angle. (a)-(b) Microscopically, the tumor cells are cytologically bland with vascular proliferation (H&E, (a) x100; (b) x400). (c)-(d) Immunohistochemistry, the tumor cells are positive for CD31 ((c), x400) as well as negative for inhibin ((d) left, x400) and EMA ((d) right, x400). The cells are also positive for CD34 and negative for GLUT-1 (not pictured).
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Histologic evaluation of the mass showed cytologically bland tumor cells with vascular proliferation, which were positive for cluster of differentiation (CD) 31 and CD34 as well as negative for inhibin, glucose transporter 1 (GLUT-1), and epithelial membrane antigen (EMA), consistent with a capillary hemangioma (Figure 4).