[Isolated trigeminal neuropathy associated with a fatty tumor of Meckel's cavum]

In recent years there has been increasing interest in isolated trigeminal sensory neuropathy. We present a case with an unusual association of this neuropathy and a fatty tumour of Meckel's cavum.

A 24 year old man consulted for occasional episodes (during the previous two months) of dysesthesia of the right maxillary region. These were self-limiting and lasted only a few minutes. There was no lacrimation, apparent trigger factor, conjunctival injection or reduction in level of consciousness. There were no abnormal findings either on general or on full neurological examination. On cranial CT there was no signal from the tip of the right petrous temporal bone, but no space-occupying lesion nor pathological uptake of contrast material. On cranial MR there was an extra-axial lesion in the superior part of the tip of the right petrous temporal bone of 2 x 2 cm, localized to Meckel's cavum and right cavernous sinus, with a small lobule in the right lateral part of the prepontine cisterna.

Trigeminal sensory neuropathy has been described in association with different connective tissue disorders, infections of the central nervous system, vascular dilatations and very varied types of tumours, particularly meningioma. The commonest site for lesions related to this clinical condition is the posterior fossa. A tumour in Meckel's cavum is rarely found in relation to this diagnosis, and from our review of the literature, involvement of fatty tumours seems to be rare.