gms | German Medical Science

Objective: Cavernous malformations (CM) arising from the cranial nerves or the conus medullaris are very rare. The clinical course of these lesions is often associated with progressive neurological deterioration due to mass effect and haemorrhage within eloquent regions. Nevertheless the radiographic appearance and the clinical presentations may be unspecific making the diagnosis difficult.

Method: We report on two rare cases of cavernous malformations involving the optical chiasm and conus medullaris that were successfully treated by surgical removal. We analyzed the clinical and radiological records regarding the symptoms, location of the lesion, surgical approach and clinical course.

Results: The first patient with a CM of the conus medullaris was a 68-year-old woman, admitted to our clinic with ipsilateral L3 radicular pain, L5, S1 radiculopathy with numbness and muscle weakness. The spinal magnetic resonance imaging (MRI) showed signs of recent hemorrhage within the conus medullaris. We removed the spinal cavernoma completely through a Th 12 laminotomy. The diagnosis of CM was histologically confirmed. At 3 months follow-up the patient recovered completely from motor and sensory deficits.

The second patient with a CM arising from the optic chiasm, was a 46-year-old man, admitted at our clinic with headache, a bitemporal hemianopsia and a visual acuity loss (right eye: 0,8; left eye: 0.7). A cranial MRI revealed a small, round tumor within the optic chiasm with peripheral rim of hypointensity on T2-weighted images. Prior to the admission the patient was treated conservatively due to an initial suspicion of an unresectable optic glioma in an outside hospital. The lesion was removed completely via right pterional craniotomy. The histological examination confirmed the diagnosis of a CM. Postoperatively the visual acuity worsened on right eye to 0.5 and improved on the left eye to 1.0. The bitemporal hemianopsia remained unchanged.

Conclusions: Although very rare, cavernous malformations of optic chiasm and conus medullaris should be taken into account as a possible differential diagnosis. To the authors' experience this is the first report on a symptomatic CM within conus medullaris that is associated with a minor trauma. In line with recent reports we recommend an operative removal of these symptomatic lesions to prevent deterioration of neurological deficits and to achieve a definite diagnosis.