Hydrocephalus due to a Cavernoma-Like Lesion of an Obliterated Cerebral Arteriovenous Malformation Treated by Embolization and Radiosurgery.

Gamma-Knife radiosurgery can be the treatment of choice for small cerebral arteriovenous malformations (AVMs) in eloquent brain areas or, in association with endovascular treatment, for large and complex AVMs. Among the possible delayed complications occurring after radiosurgery of AVMs, de novo formation of a cavernoma has only recently been described. The authors report a unique case of communicating hydrocephalus with highly proteinaceous cerebrospinal fluid due to a cavernoma-like lesion of an obliterated cerebral AVM treated by embolization and radiosurgery.A 43-year-old female patient with a left parieto-occipital AVM (Spetzler-Martin grade III) underwent a multimodality treatment comprising several endovascular procedures and Gamma-Knife radiosurgery. At the follow-up angiograms, the AVM was completely obliterated. Twelve years later, she came back to our attention for headache and vomit with the radiological evidence of brain edema, severe hydrocephalus, and a chronic encapsulated intracerebral hematoma. At the beginning, the drainage of hydrocephalus proved ineffective to improve symptoms and edema. Therefore, the surgical resection of both the obliterated AVM and the cavernoma-like lesion-histologically confirmed-was necessary. The hydrocephalus resolved as well as the cerebral edema after 3 weeks, without necessity of a ventriculoperitoneal shunt.In previous neurosurgical literature, the association of a caveroma-like lesion in an obliterated AVM and communicating hydrocephalus with highly proteinaceous cerebrospinal fluid has not yet been discussed. We believe that only the surgical resection of both the obliterated AVM and the cavernoma-like lesion can lead to complete clinical recovery of the hydrocephalus.