E-POSTER DETAIL | 11th Asia Pacific Tele Ophthalmology Society Symposium

Title
Case Report: Orbital Apex Syndrome secondary to Benign Extraocular Muscle Overgrowth

Authors
Yue Keen Tham, Chong Kiat Ng, MAHANI MASTOR

Presenting
Yue Keen Tham

PURPOSE:
Orbital Apex Syndrome (OAS), also known as Jacod syndrome, is a complex pathology characterized by the simultaneous dysfunction of the optic nerve (CN II) and the cranial nerves supplying the extraocular muscles (CN III, IV, VI). While the aetiology is typically neoplastic, infectious, inflammatory or traumatic, we report a rare case of OAS caused by benign muscle hypertrophy.

METHODS:
A 41-year-old male with well controlled diabetes mellitus and hypertension presenting with sudden lost of vision of the right eye to counting fingers (CF) vision, proptosis and ophthalmoplegia involving cranial oculomotor and trochlear nerves. Ocular motility assessment confirmed restriction patterns consistent with multiple cranial nerve involvement on the Hess chart. Magnetic resonance imaging (MRI) revealed a lesion at the right orbital apex that was inseparable from medial rectus muscle and superior oblique muscle., suspicion for lymphoma or inflammatory pseudotumour.

METHODS:

A 41-year-old male with well controlled diabetes mellitus and hypertension presenting with sudden lost of vision of the right eye to counting fingers (CF) vision, proptosis and ophthalmoplegia involving cranial oculomotor and trochlear nerves. Ocular motility assessment confirmed restriction patterns consistent with multiple cranial nerve involvement on the Hess chart. Magnetic resonance imaging (MRI) revealed a lesion at the right orbital apex that was inseparable from medial rectus muscle and superior oblique muscle., suspicion for lymphoma or inflammatory pseudotumour.

RESULTS:
Given the threat to vision, the patient underwent multidisciplinary management involving Right Functional Endoscopic Sinus Surgery (FESS). The optic nerve decompression and releasing the annulus of Zinn to relieve compressive optic neuropathy. Intraoperative findings noted significant bulkiness of the medial rectus and superior oblique muscles and removed some part of the bulky muscles.

CONCLUSIONS:
Histopathological examination (HPE) of the excised tissue revealed fragments of benign skeletal muscle with no evidence of malignancy. Following surgical decompression, the patient demonstrated significant functional recovery, visual acuity significantly improved and full restoration of extraocular motility. This case underscores the importance of considering benign muscle hypertrophy in the differential diagnosis of OAS, even when imaging mimics aggressive neoplastic processes.

CONCLUSIONS:

Histopathological examination (HPE) of the excised tissue revealed fragments of benign skeletal muscle with no evidence of malignancy. Following surgical decompression, the patient demonstrated significant functional recovery, visual acuity significantly improved and full restoration of extraocular motility. This case underscores the importance of considering benign muscle hypertrophy in the differential diagnosis of OAS, even when imaging mimics aggressive neoplastic processes.