Nasopharyngeal carcinoma with intracranial spread: CT and MR characteristics.
OBJECTIVE
Nasopharyngeal carcinoma (NPC) frequently spreads intracranially. We compare CT and MRI in identifying intracranial spread and reexamine the route of infiltration.


METHODS
One hundred fourteen consecutive patients with proven NPC were evaluated prospectively with T1-, T2-weighted, contrast-enhanced MRI and CT.


RESULTS
MRI showed 35 (31%) patients with middle cranial fossa involvement. Twenty-nine (25%) patients had cavernous sinus infiltration, while six (5%) showed only dural thickening. The most common route of spread is through the foramen ovale (FO) (12/35 patients, 34%), followed by skull base destruction (6/35 patients, 17%), foramen lacerum (FL) (6/35 patients, 17%), sphenoid sinus (6/35 patients, 17%), and combined FO and FL (5/35 patients, 14%). Using MRI as a standard, CT demonstrated the following involvement: cavernous sinus in 26 of 29 (90%) patients, FO in 9 of 12 patients, skull base in 6 of 6 patients, FO and FL in 3 of 5 patients, FL in 6 of 6 patients, sphenoid sinus in 6 of 6 patients and dura in 0 of 18 patients.


CONCLUSIONS
It is believed that NPC most commonly spreads intracranially via the FL or by direct erosion. Perineural spread through the FO is an important route, which explains why with CT evidence of cavernous sinus involvement there may be no skull base erosion. These findings are best seen on MRI.
Chong
V F
VF
Department of Diagnostic Radiology, Singapore General Hospital.
Fan
Y F
YF
Khoo
J B
JB
D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002277:Carcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D003287:Contrast Media; D006801:Humans; D008279:Magnetic Resonance Imaging; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D009361:Neoplasm Invasiveness; D011446:Prospective Studies; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed
D003287:Contrast Media