Aneurysm of the distal anterior cerebral artery radiologically mimicking a ventricular mass

Idiopathic lenticulostriate artery pseudoaneurysm protruding into the lateral ventricle: a case report

We report a rare case of an idiopathic pseudoaneurysm causing intraventricular hemorrhage (IVH). A 28-year-old man presented with sudden onset of severe headache. He underwent external ventricular drainage for an isolated IVH in the right lateral ventricle. Digital subtraction angiography (DSA) revealed that the aneurysm (7.5×4.5 mm) arose from the distal part of the medial lenticulostriate artery. Following removal of the external ventricular drainage catheter, the aneurysm decreased in size (4.0×2.3 mm). However, follow-up DSA revealed a slightly enlarged aneurysm (4.2×3.2 mm) with morphologic change. The aneurysm was clipped via the interhemispheric transcallosal approach, but postoperative DSA revealed a residual aneurysm sac beside the clips. Given the risk of rebleeding, a second operation was planned for complete resection of the aneurysm. After revised craniotomy and careful dissection of the caudate nucleus, the aneurysm sac was completely resected. Histopathological examination revealed that the aneurysm was a pseudoaneurysm. The patient recovered without any neurological sequel and was discharged.

To the best of our knowledge, this is the first reported case of an idiopathic lenticulostriate artery pseudoaneurysm protruding into the right lateral ventricle and causing an IVH that was successfully treated with microsurgical resection.

Idiopathic intraventricular aneurysm presenting with intraventricular hemorrhage: case report and review of the literature

Intraventricular hemorrhage (IVH) is a relatively commonly encountered problem in neurosurgical practice. The underlying causes could include hypertension, arteriovenous malformations (AVM), angiomas, trauma, tumors, aneurysms and moyamoya disease. Truly idiopathic intraventricular aneurysms (IVA) are rare. A high index of suspicion needs to be maintained since, with the appropriate treatment, the outcome is generally good. We report the case of a 14-year-old boy who presented with sudden onset headache and vomiting. CT angiogram pointed to the possibility of an IVA. This was confirmed by MRI with three-dimensional constructive interference in steady state (CISS-3D) sequences and digital subtraction angiography. The patient underwent microsurgical excision of the aneurysm and is doing well on follow-up. Idiopathic IVA can present with IVH at any age. MRI with CISS-3D and MR angiography would be the imaging modality of choice since it can also rule out other causes of intraventricular bleeding such as tumors and AVM. These lesions could be managed effectively by microsurgical excision/clipping. The necessity of investigating every patient who presents with IVH is debatable.