| Description |
A 2 year-old male boy was referred for painless, progressive proptosis in the right eye over a one year. The patient had no history of trauma, personal or family history of malignancy, or orbital inflammation, and had an unremarkable past medical history. On exam, the patient had fix and follow vision OU with no APD, and normal IOP of 16 and in both eyes. Motility exam demonstrated moderate deficits in all fields of gaze in the right eye, and were normal in the left eye. External exam noted subtle axial proptosis in the right eye. Slit lamp and dilated fundus exam were normal for both eyes. A fat suppressed; orbital MRI scan showed enlargement of all extraocular muscles in the right eye and significant orbital congestions with straightening of the optic nerve and axial proptosis without significant globe deformation. Laboratory workup was unrevealing with normal CBC, thyroid panel, IgG panel, lysozyme, and angiotensin-converting enzyme. An anterior orbitotomy with right lateral rectus muscle incisional biopsy was performed. Intraoperatively, the muscle was thick and difficult to cut. The tissue demonstrated low-grade spindle cell fibrosis based on trichrome Masson stain without significant nuclear pleomorphism or mitotic activity, confirmed with a Ki-67 index of less than 1%. Immunohistochemical stain were diffusely positive for vimentin and CD34, and negative for beta catenin, S-100 protein, ERG and BCL-2. The patient was monitored for several months with stable proptosis, motility limitations and vision. As the child aged, the child was noted to have a high astigmatism OD, managed with spectacles and patching. Serial MRIs were performed with stable right orbital findings. Interval dilated fundus exam revealed no optic nerve edema or atrophy. The decision was made to continue to monitor, given the stability and good vision. |
