PMC8203393_01
(a) Coronal MRI T2-weighted imaging showed bilateral hyperintense well-defined extraconal masses in the anterosuperior margin of both orbits (yellow arrows) (the greater one on the right side) corresponding to the supraorbital nerves. There was also another extraconal mass in the anteroinferior margin of the right orbit related to the infraorbital nerve, with similar appearance, and smaller on the left side (red arrows). (b) Growth of lesions in the left orbit (white arrows). (c) MRI axial T1-weighted imaging demonstrated the right anterosuperior tumor with isointensity relative to muscle with a fusiform morphology (orange arrow). (d) Intraoperative image of the lesion (blue arrow).
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T2 sequencing. There was also an ill-defined area, appearing hypodense on T2 but of intermediate density in T1, measuring 24 x 9 mm (Figures 1(a) and 1(c)). The mass had very well-defined borders in the anterosuperior margin of the right orbit, probably corresponding to the supraorbital nerve. An MRI angiogram showed no uptake of contrast, ruling out a vascular lesion, but showed a second mass in the right orbit, of similar characteristics, in the right infraorbital nerve, as well as smaller masses in the left supraorbital and infraorbital nerves (Figure 1(a)). However, there was a progressive increase in size and signal enhancement corresponding to the left supraorbital nerve during the last year, which also affected the left infraorbital nerve (Figure 1(b)), leading us to remove the tumor to make a definitive diagnosis. An orbitotomy with access through the upper eyelid skin crease was performed, exposing a fusiform lesion, cystic in appearance, measuring approximately 3 cm in its major axis, protruding from the supraorbital nerve and extending deeply into the orbit (Figure 1(d)).
Postoperative coronal RMI T2-weighted imaging showed no recurrence in superior orbit right side (arrow). There was discrete increase in size of those located in the inferior right orbit and in the superior and inferior left orbit.
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MRI follow-up demonstrated no recurrence of the excised tumor and a slight increase in size of the other lesions (Figure 2).
(a) Microscopic panoramic view of the lesion. Hematoxylin and eosin, 20x. (b) Heavy collagen bundles described as "shredded carrots" (thick arrow). Note the oval and wavy nuclei (thin arrow). Hematoxylin and eosin, 200x. (c) Whorls reminiscent of true onion bulbs (arrow). Hematoxylin and eosin, 200x.
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The microscopic analysis showed a lesion with a loose connective stroma, areas with spindle and oval cells with wavy nuclei, along with dense bundles of hyalinized collagen in the form of "shredded carrots" and others composed of concentric structures of Schwann cells around axons with an "onion bulb" appearance (Figures 3(a)-3(c)).
(a) S100 protein immunoreactivity showed Schwann cells. (b) Immunochemistry with neurofilaments was positive in axons. (c) Intermixed cells CD34 positive were observed.
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The histological findings and the presence of all the cellular elements of the nerve were compatible with a diagnosis of neurofibroma (Figures 4(a)-4(c)).