Cavernous sinus syndrome in a patient with occult nasopharyngeal carcinoma: A diagnostic challenge.

Nasopharyngeal carcinoma(NPC) is an epithelial malignancy of the nasopharyngeal mucosa. It typically exhibits local infiltration with frequent skull base involvement and often presents with multiple cranial neuropathies. It can invade the cavernous sinus via the skull base and foramen ovals, thereby causing cavernous sinus syndrome (CSS). When NPC invades nerves, the mass in the nasopharyngeal cavity may not be obvious. We report a case of CSS presenting as painful ophthalmoplegia or nonspecific inflammation. While initial glucocorticoid therapy provided transient symptom relief, the patient developed progressive neurological deficits. Ultimately, nasopharyngoscopic biopsy confirmed NPC through histopathological verification.