Non-Hodgkin lymphoma (NHL) is a hematological malignancy that can sometimes originate from the nasal cavities and paranasal sinuses. Patients who present with these tumors typically report sinonasal symptoms. However, a diagnostic challenge can arise when a patient's primary complaints include unique complex symptoms limited to the contralateral side of the tumor. This report describes the case of an 83-year-old man who presented to our center with a left-sided mass and right-sided proptosis with vision loss. After a nasal biopsy was taken, the patient was referred to the ophthalmology department to diagnose the cause of his ocular symptoms, which were not believed to be related to the mass. When biopsy results later returned as diffuse large B-cell lymphoma (DLBCL), an emergent repeat biopsy following lymphoma protocol was performed to confirm the diagnosis. A CT scan of the head and orbits showed generalized enlargement of the right optic nerve and extraocular muscles, and a positron emission tomography (PET) scan showed increased 18F-fluorodeoxyglucose (FDG) uptake in the right ethmoid sinus and orbit. The left-sided mass and right-sided symptoms resolved simultaneously with chemotherapy. This is the first documented case of a sinonasal mass causing ocular symptoms exclusively on the contralateral side. The presented diagnostic challenge highlights the importance of thorough investigations.