Orbital apex syndrome (OAS) is a clinical entity defined by ophthalmoplegia and optic nerve dysfunction due to local disruption of the orbital apex. The causes of OAS are extensive and include infectious, inflammatory, traumatic, iatrogenic, and neoplastic conditions. Thus, appropriate management is dependent on an accurate and timely diagnosis of the underlying etiology. We present a case of a 58-year-old female who presented to the emergency department with ophthalmoplegia of subacute onset and diminished visual acuity in the setting of two weeks of headache, ocular pain, and facial swelling. She was ultimately diagnosed with OAS and admitted to the hospital for five days for further evaluation. She was found to have an incurable primary SMARCB1-deficient sinonasal carcinoma with an invasion of her orbital apex. A multidisciplinary management approach involving chemotherapy, radiation, and surgical intervention was performed, and the patient responded well. Nearly two years after her diagnosis, she continues to have stable residual carcinoma without evidence of recurrence or metastatic disease. Her visual acuity has returned to normal limits, and her oculomotor function has returned to near-normal levels.