A Rare Case of Orbital Adenoid Cystic Carcinoma Mimicking as Optic Nerve Glioma.

Adenoid cystic carcinoma is an uncommon epithelial cell tumour that usually originates from glands. They arise from the upper respiratory tract, lungs, mammary glands, and skin, but most commonly from the salivary glands and lacrimal glands. Our article reports a 53-year-old individual presenting with a history of diminution of visual acuity over the past one and a half months, also associated with a right-sided headache and throbbing eye pain not relieved by medication. Examination revealed right axial proptosis, ptosis, and visual acuity of 6/36, right afferent pupillary defect (RAPD), restriction of ocular movements in supraduction, dextroelevation, and abduction. The fellow eye was completely normal. MRI revealed an enhancing lesion in the retrobulbar area of the right orbit indicative of optic nerve glioma of stage 2. The patient underwent orbito-zygomatic craniotomy with subtotal excision of the mass by a neurosurgeon. Following surgery, histopathological examination of the excised tumour revealed features consistent with adenoid cystic carcinoma. On the third post-operative day, the subject's vision improved to counting fingers at 3 metres, and extraocular movements were regained.