Compressive Optic Neuropathy Secondary to Sinonasal Undifferentiated Carcinoma in a Young Male.

Sinonasal undifferentiated carcinoma (SNUC) is an extremely aggressive malignancy. Extension to the orbit and adjacent structures is common, but isolated visual loss as a presenting symptom is rare. We report a rare case of SNUC with bilateral visual loss as the initial manifestation. A 34-year-old gentleman was presented with acute onset loss of vision in both eyes for one week. It was followed by recurrent headaches and epistaxis. Visual acuity in the right eye was 2/60 and 3/60 in the left eye. Funduscopy showed a bilateral swollen disc. Neuroimaging revealed a large mass in the ethmoidal sinus extended laterally causing compression to recti muscles and the optic nerves. The histopathological examination of nasal tissue biopsy showed features of SNUC with bone and perineural invasion. A diagnosis of SNUC with bilateral compressive optic neuropathy was established. The patient underwent tumor debulking and base of skull reconstruction by the neurosurgical team. This was then followed by chemotherapy and radiotherapy. The patient's right eye visual acuity initially improved to 6/9. However, his both eye vision developed into no light perception during treatment. In conclusion, SNUC is a highly aggressive tumor that may present with acute blindness. Early treatment may save a life, but the visual prognosis is guarded due to extensive optic nerve damage caused by tumor compression.