Cavernous malformation of the III cranial nerve: A challenging pathology

Abstract

Cavernous malformations (CM’s) are angiographically occult vascular malformations found in approximately 0.4%–0.9% of the population, and they account for 10%–20% of all cerebrovascular malformations. Isolated cranial nerves CMs are extremely rare, and there are very few reports of oculomotor nerve CMs.We present the case of a 69 years-old man, with an insidious and progressive palsy of the III left CN with 6 months of evolution. CT scan revealed a 1,2 cm lesion located at the suprasellar and pre-pontine cistern at the free edge of the tentorium, initially compatible with the diagnosis of a small meningioma. He was submitted to surgery but surprisingly histopathological analysis revealed a cavernous malformation, intrinsic to the nerve.This is the twelfth reported case of an III cranial nerve CM, and the management of this lesions still doesn’t have clear and definitive recommendations regarding treatment. In selected cases, the lesion can be excised without compromise of the affected cranial nerve, but when complete excision is compromised, the surgeon has to decide between function sacrifice or leaving a residual behind, knowing that this last decision can lead to recurrence and further morbidity.