SUPERIOR ORBITAL FISSURE SYNDROME CAUSED BY INTRAORBITAL SPREAD OF A CUTANEOUS SQUAMOUS-CELL CARCINOMA AND NOT DETECTED ON COMPUTED-TOMOGRAPHY AND MAGNETIC-RESONANCE-IMAGING

Intraneural and perineural spread of a squamous cell carcinoma of the frontal region via the orbit to the cranial cavity is a rare cause of a superior orbital fissure syndrome. This mode of tumor spread, for wh ich a previously excised invasive malignant tumor is responsible, is r arely reported. The absence of an intraorbital mass and the fact that computed tomography (CT) and magnetic resonance imaging (MRI) are norm al make the diagnosis extr remely difficult. We describe a 76-year-old patient in whom both intraneural and perineural tumor growth deep int o the orbit caused acute ocular motility disturbances, visual impairme nt, and ocular dysfunction with subsequent cerebral and vascular dysfu nction. Surgery, radiotherapy, and orbital exenteration did not preven t spread of the tumor toward vital intracranial and intracerebral stru ctures. Even the advanced diagnostic modalities of CT and MRI failed t o reveal the cause of the pathologic process in our patient. In such a case, one should look carefully for both intraneural and perineural t umor invasion on previous histologic material and, if positive, treat the patient with radical surgery on purely clinical grounds as early a s possible. (C) 1997 Japanese Ophthalmological Society.