Presentation, Surgical Management, and Postoperative Outcome of a Fourth Ventricular Cavernous Malformation: Case Report and Review of Literature.

BACKGROUND

Brainstem cavernous malformations (CMs) represent dangerous clinical entities associated with high rates of rebleeding and morbidity compared with those in other locations. Particularly rare are those located within the fourth ventricle. Although fourth ventricular CMs are favorable from a surgical standpoint, there are no defined guidelines on definitive indications and optimal timing of surgery. In addition, the surgical approaches, anatomic considerations, and general observations regarding these lesions are not well reported in the literature.

CASE PRESENTATION: A 27-year-old man with a known history of a CM on the floor of the fourth ventricle presented with new cranial nerve deficits and signs of increased intracranial pressure. Imaging revealed acute bleeding from a fourth ventricular CM. The patient was urgently taken to surgery for resection. Despite a noneventful surgery which resulted in gross total resection, the patient developed a unique constellation of cranial nerve deficits postoperatively, most notably of which was eight-and-a-half syndrome.

CONCLUSIONS

CMs of the fourth ventricle are rare clinical entities that can be treated successfully with surgery. The indications for surgery may not always be clear-cut; therefore, the neurosurgeon's decision to proceed with surgery must reside on a case-by-case basis using a multifactorial approach. The location of these lesions presents unique challenges given their proximity to vital structures and the technical difficulty required. For these reasons, the resection of these lesions often results in new or persistent neurologic deficits. However, despite the associated risks, the potential benefits of surgery oftentimes outweigh the risks of the alternative.