Hidden Bow Hunter's Syndrome Diagnosed Using Dynamic Cerebral Angiography and Successfully Treated with Spinal Surgery: A Case Report and Review of the Literature.

Hidden bow hunter's syndrome (HBHS) is a rare disease in which the vertebral artery (VA) occludes in a neutral position but recanalizes in a particular neck position. We herein report an HBHS case and assess its characteristics through a literature review. A 69-year-old man had repeated posterior-circulation infarcts with right VA occlusion. Cerebral angiography showed that the right VA was recanalized only with neck tilt. Decompression of the VA successfully prevented stroke recurrence. HBHS should be considered in patients with posterior circulation infarction with an occluded VA at its lower vertebral level. Diagnosing this syndrome correctly is important for preventing stroke recurrence.

Early Response to Radiation Therapy without Surgical Intervention in a Giant Cavernous Sinus Hemangioma with Hydrocephalus: A Case Report.

Cavernous sinus hemangioma (CSH) is a rare vascular malformation, arising from the cavernous sinus. Because of its anatomically complex location, a large lesion can cause a variety of symptoms due to cranial nerve compression. A 69-year-old woman with an unsteady gait was admitted to our hospital, and magnetic resonance imaging revealed an extra-axial giant tumor in the cavernous sinus and enlarged ventricles. A radiographic diagnosis of CSH was made. As the risk of surgical removal was considered high, the patient underwent intensity-modulated radiation therapy of 50.4 Gy in 28 fractions. The size of the tumor decreased markedly over time, and the symptoms improved soon after treatment. A 61.8% reduction in tumor size was confirmed immediately after irradiation, and a 75.9% reduction was revealed at a follow-up visit one year later. We reported a case of a giant CSH with hydrocephalus, where tumor shrinkage was confirmed immediately after radiation therapy, and the symptoms of hydrocephalus improved without surgical intervention.

Disappearance of a Ruptured Feeding Artery Fusiform Aneurysm After the Resection of a Large Subependymoma: A Case Report.

Aneurysm formation on the tumor-feeding artery is rare, and its treatment strategies are not yet settled. We herein report the case of a 49-year-old female with a large subependymoma in the left lateral ventricle presenting remote intracerebral hemorrhage at the left posterior cingulate gyrus. Digital subtraction angiography (DSA) revealed the presence of a 5.5 mm fusiform tumor-feeding artery aneurysm on the left parieto-occipital branch of the posterior cerebral artery, considered to be the source of the hemorrhage. Three months after total tumor resection, the aneurysm subsequently disappeared on the follow-up angiography. Subependymomas are generally known as tumors with low vascularity and seldom present with symptoms such as intracerebral hemorrhage. From the subsequent disappearance of the aneurysm after the complete tumor resection, the pathophysiological cause of the aneurysm formation is assumed to be flow-related hemodynamic vessel wall stress of the feeding artery. Tumor resection alone may be a favorable first treatment strategy to avoid unnecessary brain damage since subsequent disappearance of the aneurysm can be expected. The coexistence of feeding artery aneurysms should be kept in mind, especially in cases with remote hemorrhage.

Anomalous Cervical External Carotid Artery-Internal Carotid Artery Anastomosis Diagnosed Using Digital Subtraction Angiography: A Case Report.

Anomalous external carotid artery (ECA)-internal carotid artery (ICA) anastomosis is a rare variant of cervical carotid artery formation that forms an arterial ring in the cervical segment, and its embryological mechanism is still unknown. We report a case of a 41-year-old woman who was incidentally diagnosed with this arterial variation using digital subtraction angiography. The angiography revealed the occipital artery arising from the anastomotic vessel and the ascending pharyngeal artery arising from the ICA near the anastomosis. The proximal ICA was smaller in diameter than the proximal ECA, but it was not stenotic and had sufficient caliber for the distal blood flow. It is commonly believed that the persistence of primitive vessels is the result of agenesis or hypoplasia of the proximal artery. In our case, the anomalous vessel was considered to be the remnant of a primitive anastomosis between the ECA and the ICA via the pharyngo-occipital system, and the narrowing of the proximal ICA may be the result of the remaining ECA-ICA anastomosis.

Significance of perilesional T1 hyperintense areas in the differential diagnosis of primary adult-type diffuse glioma: A case report.

Perilesional T1 hyperintensity on magnetic resonance imaging (MRI) of intra-axial brain masses is an unusual feature of the perilesional area, characteristic of cavernous malformations (CMs) and metastatic brain tumors (METs). Here, we report a case of primary diffuse glioma with a perilesional T1 hyperintense area (HIA) on MRI. A 61-year-old woman with transient aphasia visited our hospital. Radiological examination revealed an intra-axial mass with acute/subacute hemorrhaging and calcification in the left frontal lobe. It was presumed to be a CM because of the perilesional T1 HIA. Gross total resection of the tumor was performed, and the pathological diagnosis was anaplastic oligodendroglioma, not otherwise specified by World Health Organization 2016 classification. Histopathological findings in the perilesional T1 HIA indicated hemorrhage involvement in the surrounding white matter. No recurrence appeared after radio-chemotherapy. Perilesional T1 HIAs, characteristic of CMs and METs, are also seen in primary diffuse gliomas. Therefore, caution should be taken when using this sign for the differential diagnosis of intracranial masses.

Direct Carotid-Cavernous Fistula Caused by Internal Carotid Artery Perforation by a Microcatheter Body during Mechanical Thrombectomy.

Rapid advances in emergent mechanical thrombectomy have resulted in a higher occurrence of arterial perforations during neurointerventions. Here, we report a case of internal carotid artery (ICA) perforation during mechanical thrombectomy in a 78-year-old man with a left middle cerebral artery occlusion. The ICA was perforated by a microcatheter during thrombectomy, forming a direct carotid-cavernous fistula. A two-stage drainer occlusion was conducted because of cortical venous reflex aggravation and ocular symptoms. Here, we report the perforation details and treatment, adding to evidence that ICA perforation with the microcatheter body is a concern during mechanical thrombectomy.

Fatal recurrent ischemic stroke caused by vertebral artery stump syndrome.

BACKGROUND: Vertebral artery stump syndrome (VASS) develops into recurrent posterior circulation ischemic stroke after ipsilateral vertebral artery (VA) occlusion at its origin. CASE DESCRIPTION: The patient was a 46-year-old man with the right posterior cerebral artery occlusion. We used a recombinant tissue plasminogen activator (rt-PA) and then performed mechanical thrombectomy using a stent retriever. Angiography revealed left VA occlusion and stagnant flow to the left VA from the right deep cervical artery; therefore, we diagnosed VASS. Within 24 h of the rt-PA injection, the symptoms had dramatically improved, and so we avoided additional antithrombotic agents. Only 13 h later, the patient developed a basilar artery occlusion and died in spite of a repeated mechanical thrombectomy. CONCLUSION: Vigilance against early (and sometimes fatal) recurrent stroke induced by VASS is required.

Microvascular Decompression for Oculomotor Nerve Palsy due to Nonaneurysmal Vascular Compression.

BACKGROUND: Diabetes mellitus and aneurysmal compression are well-known causes of oculomotor nerve palsy (ONP), but nonaneurysmal vascular compression of the oculomotor nerve has rarely been reported. CASE DESCRIPTION: A 70-year-old nondiabetic man presented with left ONP for the past 2 days. Magnetic resonance imaging revealed the left posterior communicating artery to be compressing the left oculomotor nerve. Microvascular decompression of the offending artery from the nerve via a left frontotemporal craniotomy was performed; the nerve showed a color change suggestive of degenerative alteration. ONP was fully resolved within 1 month of surgery. CONCLUSIONS: Whether nonaneurysmal vascular compression of the oculomotor nerve is a true cause of ONP is sometimes controversial. However, recent developments in magnetic resonance imaging can clearly demonstrate the spatial relationship between the oculomotor nerve and vessels. Detailed magnetic resonance imaging should be used to diagnose compression of the oculomotor nerve by blood vessels. Microvascular decompression is the treatment of choice in this situation.

Anterior Cranial Fossa Dural Arteriovenous Fistula with Pial Arterial Supply.

Anterior cranial fossa (ACF) dural arteriovenous fistulas (DAVFs) are mainly fed by the ethmoidal arteries and sometimes have pial arterial feeders. DAVFs with pial arterial supply in ACF are extremely rare because most of the reported cases of DAVFs with pial arterial supply are located at the transverse sigmoid sinus and tentorium. A 68-year-old male presented with dizziness. Angiography showed cortical venous reflex (CVR) through an ACF DAVF fed by both bilateral ethmoidal arteries and by the right orbitofrontal artery as a pial feeder. The ethmoidal feeders were disconnected by craniotomy. The pial arterial feeder from the anterior cerebral artery was not found during surgery, and disconnection of the draining vein was not performed. CVR showed a significant reduction after the surgery. After 2 years of follow-up, angiography revealed an increased shunt flow from the pial feeder. Endovascular treatment using n-butyl-2-cyanoacrylate was performed, resulting in the complete occlusion of the fistula. DAVFs with pial supply are reported to carry a high risk of perioperative complications because of the restriction of the venous outflow and retrograde thrombosis of the pial artery. Endovascular pial feeder occlusion after surgical dural arterial feeder disconnection might achieve a safe and effective outcome. With close follow-up, the recurrence of increased shunt flow may be an appropriate timing for additional treatment. This rare condition may offer a new insight into the mechanisms of pial feeder development.

A Patient with a Distal Medial Lenticulostriate Artery Aneurysm and Intraventricular Hemorrhage Treated by Endovascular Treatment.

Objective: A patient with a ruptured distal medial lenticulostriate artery (mLSA) aneurysm presenting with intraventricular hemorrhage was successfully treated using endovascular treatment. Case Presentation: A 60-year-old woman presented with impaired consciousness. Radiological examination revealed intraventricular hemorrhage caused by a rupture of a distal mLSA aneurysm. Using endovascular technique, approaching contralaterally through the anterior communicating artery (AComA), complete occlusion of the aneurysm was achieved by N-butyl-2-cyanoacrylate (NBCA) injection. The postoperative course was uneventful. Conclusion: Intraventricular aneurysms at a distal site of the perforating arteries are rare. Although there have been reports on patients with distal mLSA aneurysms treated by open surgery or conservative therapy, endovascular therapy should also be considered as a treatment option.

Bleb formation in small unruptured intracranial aneurysm as a predictor of early rupture.

Small unruptured aneurysms are thought to have a low risk of rupture, but the management of such lesions is still controversial. A 73-year-old man with a small anterior communication artery aneurysm, 4 mm in diameter, while on follow-up, developed an aneurysmal subarachnoid hemorrhage 2 weeks after the detection of a newly emerged bleb on the surface of the aneurysm. In conclusion, the formation of a bleb should be considered as a warning sign of an impending rupture, and treatment should be provided even for patients with small aneurysms.