PMC5833217_01
Imaging, gross and microscopic examination, and schema of the enucleated eyeball containing the intraorbital ancient PA arising from the optic nerve. (a) T2-weighted MRI scanning 10 months before his emergency surgery showed that the crescent-like intraorbital solid content measured approximately 20 mm x 10 mm in the left posterior eyeball (arrows), generating a low (grayish) signal intensity in marked contrast to a high (white) signal intensity of the vitreous body. There were neither apparent signs of optic nerve or surrounding orbital tissue involvement, nor any intracranial tumor lesions. (b) The enucleation of the left eyeball was performed, and a gross examination of the sagittal cut surface revealed an oval, well-demarcated nodular and solid lesion, yellow-whitish in color, measuring approximately 10 mm x 5 mm in diameter and likely floating in the abundant bloody to serous fluid, coexisted with a subsequent cystic component. A gross connection between its solid tumor part and the optic nerve (arrowhead) was not evident. Bar = 10 mm. (c) On scanning magnification of the surgical specimen (H&E stain), this intraorbital tumor contained a large amount of eosinophilic serous fluid admixed with a number of red blood cells, displaying a likely floating and well-circumscribed but distorted nodule, uniquely accompanied by frequent, large to small cystic degeneration. Retina was mostly detached and overtly separated by this intraorbital ancient PA arising from the optic nerve (arrowhead). Bar = 10 mm. (d) The schema of its ancient optic nerve PA components (cystic PA, red; solid PA, yellow; and fluid, gray) was shown, involving the orbital portion of the optic nerve (arrowhead), detaching/separating the retina (bold black line), and likely demonstrating a sequential degeneration with possible rupture. This intraorbital ancient PA strongly compressed the pre-existing vitreous body, resulting in severe lens luxation; however, there was no apparent infiltrative growth fashion. Bar = 10 mm (H&E stain).
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T2-weighted magnetic resonance imaging (MRI) (Figure 1(a)). There were neither apparent signs of optic nerve or surrounding orbital tissue involvement, nor any intracranial tumor lesions (Figure 1(a)). On gross examination of the surgical specimen, the sagittal cut surface of the left eyeball characteristically displayed an oval, well-demarcated nodular and solid lesion, yellow-whitish in color, measuring approximately 10 mm x 5 mm in diameter and likely floating in the abundant bloody to serous fluid, coexisted with a subsequent cystic component (Figure 1(b)). A gross connection between its solid tumor part and the optic nerve was not evident (Figure 1(b)). On its scanning magnification, this intraorbital tumor was found to contain a large volume of eosinophilic serous fluid with a number of red blood cells and showed a well-circumscribed but distorted nodule, uniquely accompanied by frequent, large to small cystic degeneration (Figure 1(c)). After the thorough histopathological examination, retina was mostly detached and overtly separated by this intraorbital ancient PA of the optic nerve (Figure 1(c) and (d)). The intraorbital ancient PA strongly compressed the vitreous body, resulting in severe lens luxation (Figure 1(c) and (d)). The schema of each cystic or solid PA component was shown, involving the orbital portion of the nerve, and likely demonstrating a sequential degeneration with possible rupture (Figure 1(d)).
The histopathological and immunohistochemical examination of the intraorbital ancient PA arising from the optic nerve in the enucleated eyeball. (a) Under a low-power view (H&E stain), the solid PA component was also identified in the optic nerve (arrows), and this solid part arising from the optic nerve uniquely permeated the retina and was protruded from the orbital portion of the nerve into the eyeball (arrowheads). Foci of arachnoidal hyperplasia around the optic nerve were absent. Bar = 500 microm. (b) Microscopic findings of medium-power view showed that the PA predominantly composed of a cellular to acellular proliferation of characteristic spindle-shaped, bipolar astrocyte-like cells having mildly enlarged, pleomorphic nuclei and elongated, hair-like processes with very few mitotic figures in a biphasic fashion, associated frequently with cystic and hyalinized degeneration (top and left bottom) and eosinophilic fluid production (left bottom). Those pilocytic cells of PA appeared as palisading features around cystic spaces or blood vessels. Bar = 200 microm (H&E stain). (c) A high-power view (H&E stain) uniquely detected scattered coagulative tumor necrosis with a pseudopalisading feature (left), and glomeruloid microvascular proliferation (right) in this intraorbital ancient PA of the optic nerve, reminiscent of high-grade gliomas. Bar = 25 microm. (d) In immunohistochemistry, those pilocytic tumor cells were diffusely and strongly positive for GFAP. Bar = 100 microm.
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Microscopic findings showed that the solid PA component was noted in the optic nerve and that this solid part arising from the optic nerve uniquely permeated the retina and was protruded from the orbital portion of the nerve into the eyeball (Figure 2(a)). Foci of arachnoidal hyperplasia around the optic nerve were absent (Figure 2(a)). Medium-power view revealed that the tumor predominantly comprised a cellular to acellular (biphasic) proliferation of characteristic spindle-shaped, bipolar astrocyte-like cells having mildly enlarged, pleomorphic nuclei and elongated, hair-like processes with very few mitotic figures (Figure 2(b) and (c)), associated frequently with cystic and hyalinized degeneration and eosinophilic fluid production (Figure 2(b)). Those pilocytic cells appeared as palisading features around cystic spaces or blood vessels (Figure 2(b)). Interestingly, a high-power view detected scattered coagulative tumor necrosis with pseudopalisading features, and glomeruloid microvascular proliferation, reminiscent of high-grade gliomas (Figure 2(c)). Immunohistochemically, these neoplastic cells were diffusely and strongly positive for glial fibrillary acidic protein (GFAP, diluted 1:40; Nichirei Bioscience, Tokyo, Japan; Figure 2(d)), whereas completely negative for epithelial membrane antigen (EMA, diluted 1:1; Dako Cytomation Co., Glostrup, Denmark), isocitrate dehydrogenase 1 (IDH-1, diluted 1:100; Dianova, Lyngby, Denmark), and p53 (diluted 1:1000; Dako).