Extra-cranial trigeminal schwannomas with middle temporal fossa development.

Schwannomas of trigeminal nerve account for 0.07% to 0.36 % of all intra-cranial tumors. We report three observations about Jefferson's type D tumors, mainly extra-cranial with only small intra-cranial extension, concerning two men and one woman, who were respectively 36, 60 and 63 years old. Two of them presented with facial pain and hypoesthesia in the same territory. The third one developed a diplopia. In all cases, CT scanner analysis evidenced a large hypodense tumor extending in the infratemporal fossa. Temporal lobe and cavernous sinus were pushed aside by the intra-cranial extension. Tumors were hypo intense in T1-weighted image with significant enhancement after gadolinium injection. One of the tumors was a cystic form and in that case, an hyper signal in T2-weighted image was detected in the middle of the lesion. A combined subtemporal and transmaxillary approach was performed in 2 cases. In the third case, the removal of the tumor was only performed by a transmaxillary approach. In this serie, there was no surgical mortality. One patient presented a postoperative residual painful anesthesia. In conclusion, extra-cranial schwannomas with intra-cranial extension are specially rare lesions. The most common early symptoms are facial neuralgia, facial hypoesthesia or diplopia. Neuroradiologic investigations, including CT and MRI evidence the precise anatomic site of the lesions. With the help of these techniques, total surgical tumor removal is possible in the majority of cases.