A 37-year-old male with a known history of neurofibromatosis type 2 presented with progressive right-sided proptosis. Serial MRI studies (Fig. 1) from 6 years (Fig. 1A,D), 3 years (Fig. 1B,E), and 1 year (Fig. 1C,F) before presentation demonstrated an enlarging tumor within the medial rectus muscle. On T1-weighted fat-suppressed gadolinium-enhanced sequences, diffuse contrast enhancement (A) was followed by a small patch of hypoenhancement (B, black arrow), and finally a thin peripheral rim of enhancement (C). On T2-weighted fat-suppressed sequences, the lesion initially isointense to muscle (D) developed a small central patch of hyperintensity (E, white arrow), followed by avid hyperintensity filling the tumor (F). The T2 hyperintensity in (E) was thought to represent the histologic Antoni B pattern, which then underwent cystic degeneration to produce the avid T2 hyperintensity in (F). The Antoni A pattern is represented by regions of T2 hypo- or isointensity and contrast enhancement.FIG. 1.: Serial MRI imaging of orbital schwannoma within the right medial rectus muscle, (A,D), 6 years, (B,E), 3 years, and (C,F), 1 year prior to presentation.Surgical resection was performed through a transcaruncular approach with cryoprobe assistance (Fig. 2A). The tumor, which was encased within the medial rectus muscle, leaked clear fluid during removal. Gross examination (Fig. 2B) showed a complete capsule (arrow) with cystic degeneration (dotted line), and histopathologic evaluation confirmed the diagnosis of schwannoma, with Antoni A and B patterns (Fig. 2C and D, respectively), Verocay bodies, and immunohistochemical staining positive for S100 and negative for CD34. At 3 months follow up, the patient’s proptosis was resolved and extraocular motility was intact in all directions of gaze.FIG. 2.: Operative photographs and photomicrographs. A, Intraoperative photograph during tumor removal. B, Gross photograph of bisected tumor. Histopathology of schwannoma with (C), Antoni A and (D), Antoni B patterns.