PMC4838925_01
PMC4838925_02
Axial T2 (a) and postcontrast axial T1 (b) magnetic resonance imaging sequences at initial patient presentation, demonstrating bilateral cerebellopontine angle masses extending into the internal auditory canal
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F1
Magnetic resonance imaging (MRI) of the brain revealed bilateral nonenhancing IAC/CPA masses [Figure 1a and b].
Axial T2 (a) and postcontrast axial T1 (b) magnetic resonance imaging sequences 1 year after initial patient presentation, demonstrating slight growth of bilateral internal auditory canal/cerebellopontine angle tumors
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F2
The mass on the left measured 6 mm x 5 mm x 4 mm; the right-sided mass measured 10 mm x 8 mm x 7 mm with growth of the intracanalicular portion to 8 mm in length [Figure 2a and b].
Surgical pathologic studies consistent with ganglioglioma. (a) H and E staining. Several ganglion cells, with cytoplasmic Nissl substance and smudgy nuclei, exist within a low grade appearing glial stroma. (b) Ganglion cells within the tumor show strong neurofilament protein immunoreactivity and haphazardly oriented cell processes. (c) Glial fibrillary acidic protein is strongly immunoreactive within a background astrocyte-like cell processes. (d) Only a rare cell was immunoreactive for Ki-67 (MIB-1)
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F3
One-half was submitted for intra-operative consultation, which yielded a diagnosis of "ganglioneuroma versus ganglioglioma." Examination of formalin-fixed, paraffin-embedded tissue sections reveled circumscribed neuroglial tissue composed of mature ganglion cells existing in a background of low-grade astrocyte-like cells with coarse processes [Figure 3a-d]. Ganglion cells contained Nissl substance and vesicular nuclei with prominent nucleoli and were randomly distributed in a haphazard fashion without polarization of cell processes [Figure 3a]. Neurofilament protein was strongly immunoreactive in the ganglion cells and revealed un-oriented cells' processes extending into the glial stroma [Figure 3b]. Glial fibrillary acidic protein (GFAP) was strongly reactive in abundant astrocytic cell processes [Figure 3c]. The tumor was mitotically quiescent and the Ki-67 labeling index <1% [Figure 3d].