Perineural spread of basosquamous carcinoma to the orbit, cavernous sinus, and infratemporal fossa

Basosquamous carcinoma is a rare, highly aggressive variant of basal cell carcinoma with elevated rates of recurrence, perineural invasion, and metastasis. We describe a patient who presented with unilateral complete ophthalmoplegia, ptosis, optic neuropathy, and trigeminal neuropathy due to perineural intracranial invasion of nasal basosquamous carcinoma via the sphenopalatine fossa to the cavernous sinus, orbit, and infratemporal fossa. To our knowledge, this is the first reported case of basosquamous carcinoma with perineural invasion involving the cavernous sinus in the English language ophthalmic literature. Physicians should be aware of the diagnostic features, clinical challenges and aggressive nature of basosquamous carcinoma, a rare diagnosis that can lead to significant morbidity/mortality when left unrecognized.