Secondary normal pressure hydrocephalus following pituitary apoplexy: A case report.

Background: Although secondary normal pressure hydrocephalus (sNPH) can occur in various central nervous system diseases, there are no reports of sNPH caused by pituitary lesions. Herein, we present a unique case of sNPH caused by pituitary apoplexy. Case Description: A 70-year-old man was transferred to our hospital because of a sudden onset of headache and loss of consciousness. The cerebrospinal fluid (CSF) test showed slightly elevated cell counts and protein levels but a negative CSF culture test. Magnetic resonance imaging showed a dumbbell-like cystic lesion with hemorrhagic change at the sella turcica. From the above, the patient was diagnosed with aseptic meningitis caused by pituitary apoplexy. Pituitary hormone replacement therapy was undertaken, and his symptoms fully improved. However, two months later, he complained of a gait disturbance and incontinence that had gradually appeared. Brain imaging with computed tomography showed no ventricular enlargement compared with initial images, although the lateral ventricles were slightly enlarged. As a CSF drainage test improved his symptoms temporarily, sNPH with possible longstanding overt ventriculomegaly in adults (LOVA) background was suspected. We performed a lumboperitoneal shunt (LPS) placement, which improved his symptoms. Conclusion: This case suggests that sNPH can develop even after a small subarachnoid hemorrhage caused by a pituitary apoplexy in LOVA patients. If the aqueduct of Sylvius is open, sNPH with a LOVA background can be successfully treated with LPS placement.

Successful Retrieval of Filter Embolic Protection Device Fragment Trapped by a Carotid Stent: A Case Report.

Objective: Embolic protection devices are useful for preventing distal embolism during carotid artery stenting (CAS); however, complications have been reported. The successful removal of a filter fragment trapped at the distal edge of a carotid stent during the retrieval procedure is described. Case Presentation: CAS was performed for internal carotid artery stenosis in a patient in his 70s, and the carotid stent was successfully placed. During the retrieval procedure, the tip of the filter was trapped at the distal edge of the stent and detached from the filter. Using a snare kit, the filter tip was successfully retrieved, and no postoperative neurological symptoms occurred. Conclusion: The edge of a carotid stent can potentially trap devices. When trapping or fragmentation of a device is suspected, it is necessary to evaluate the situation and cause, and the device should be appropriately retrieved without using force.

Postcoiling syndrome including headache and fever after endovascular cerebral aneurysmal coil embolization: A narrative review.

Endovascular cerebral aneurysmal coil embolization is becoming more popular than direct aneurysmal neck clipping due to its noninferiority in long-term outcomes and being less invasive. Neuroradiologists often find postoperative symptoms such as headache and fever after unruptured aneurysmal coil embolization, however, they have not paid much attention because symptoms almost always resolve spontaneously within a few days. Since the concept of this syndrome has not been standardized, we named it postcoiling syndrome (PCS). In this short review, we reviewed the criteria, risk factors, mechanisms, significance, and treatment of PCS based on a few pieces of literature. Almost all literature has regarded that some kind of bioactive reaction might be involved in PCS. Preliminary data showed the possibility of inhibition of PCS by histamine-2 receptor antagonists. PCS also might have the potential of more predictive maker than previously reported risk factors for recurrence after aneurysm coil embolization. Further investigation is needed in the future, including the accumulation of cases, unification of concepts, and mid-to-long-term follow-up.

Adult Infratentorial Pial Arteriovenous Fistula Treated with Detachable Coils: A Case Report and a Review of Literature.

An appropriate therapeutic option for pial arteriovenous fistula (PAVF) can vary according to the angioarchtecture of the lesion. We present a case of adult infratentorial PAVF treated by transarterial coil embolization. A 26-year-old man was referred to our institution for an asymptomatic intracranial vascular lesion. Cerebral angiograms revealed PAVF fed by three arteries in the right cerebellomedullary cistern. The feeding arteries were accurately identified by three-dimensional rotational angiography and were successfully embolized using coils while normal arterial flow was preserved. This case report suggests that stepwise transarterial coil embolization can cure PAVF under detailed evaluation of its angioarchitecture.

A Unique Case of Intracranial Amelanotic Melanoma with BRAF V600E Mutation Successfully Treated via Molecular-targeted Therapy.

Melanoma carries a high risk of brain metastasis. A small subset of metastatic melanomas, known as amelanotic melanomas, does not present black coloration, reflecting a lack of melanin pigmentation. Here, we report a case of B-Raf proto-oncogene (BRAF) V600E mutation associated with a metastatic brain tumor caused by the amelanotic melanoma. A 60-year-old man was transferred to our department following acute onsets of left upper limb paralysis and convulsion. In the brain imaging, multiple lesions in the right frontal lobe and left basal ganglia were detected, and the presence of an enlarged left axillary lymph node was revealed. Consequently, we removed the right frontal lesion and performed a biopsy of the left axillary lymph node. Histological analysis of both specimens indicated an amelanotic melanoma, and genetic testing revealed a BRAF V600E mutation. The residual intracranial lesions were treated with stereotactic radiotherapy and molecular-targeted therapy, with dabrafenib and trametinib as the systemic treatment. Based on the Response Evaluation Criteria in Solid Tumors, we determined that the patient achieved complete remission (CR) under uninterrupted molecular-targeted therapy over a period of 10 months. After the temporary withdrawal of dabrafenib and trametinib to avoid hepatic dysfunction, a new intracranial lesion appeared. CR of this lesion was achieved following reinstatement of the two drugs. These results suggest that, under limited conditions, molecular-targeted therapy can produce a sustained response against the intracranial metastasis of melanoma, and the therapy with reduced dose is still effective against a recurrent case after cessation of the therapy due to the toxicity.

Age is a major determinant for poor prognosis in patients with pilocytic astrocytoma: a SEER population study.

Background Pilocytic astrocytomas (PAs) are central nervous system tumors with variable prognosis and poorly understood risk factors. Little evidence exists regarding the effect of age on mortality in PA. Therefore, we conducted a thorough characterization of PA in the US. Methods We queried the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2018 to extract age-adjusted incidence rate (AAIR), age-adjusted mortality rate (AAMR), and survival data on PA. The age group comparisons for each measure varied depending on available SEER data. We compared trends in AAIR and AAMR by two age groups (children, 0-19 years; adults, 20 + years) and by sex. The cumulative incidence function and the Fine-Gray competing risk model were applied by 0-19, 20-39, 40-59, and 60 + years of age groups. Results This study included 5211 incident PA and 462 PA-specific deaths between 2000 and 2018. Trends in AAIRs and AAMRs were almost constant between 2000 and 2018. Average AAIRs had a sharp peak in 1-4 years of age groups, whereas AAMRs had a gradual peak in 80-84 years of age groups. Age groups, tumor location, and race/ethnicity were significantly associated with PA-specific death, whereas only age was associated with other cause of deaths. Conclusions Trends in AAIRs and AAMRs were constant regardless of age. PAs in older populations, especially over 60 years old, have higher incidence of death than those in younger populations.

A Case of Intracranial Vertebral Artery Stenosis Treated with Percutaneous Transluminal Angioplasty and Stenting Guided by Brain Oximetry.

Surgical treatment should be considered for patients with severe vertebrobasilar artery (VBA) stenosis or progressive symptoms, but there is currently no clear treatment algorithm. We report a case of symptomatic intracranial vertebral artery stenosis with repeated cerebral infarction treated by percutaneous transluminal angioplasty (PTA) and stenting and monitoring of oxygen saturation by a brain oximeter. The patient was a 76-year-old man referred to our hospital due to infarction in the right cerebellum. Angiography showed 60% stenosis in the right vertebral artery and 90% stenosis in the left vertebral artery with progressive stenosis in the left. The patient was treated with intravenous and oral triple antiplatelet therapy but had dizziness again with new cerebral infarctions in the left cerebellum and right pontine. We shaved the patient's hair up to the superior nuchal line and placed left and right oximeter probes on each cerebellar hemisphere (2 cm lateral and 2 cm caudal from the external occipital protuberance). Under evaluation of blood flow in the posterior circulation with INVOS Cerebral/Somatic Oximeter, PTA and stent placement were performed for left vertebral artery stenosis. Postoperatively, the dizziness disappeared, and the patient was discharged on his own with good outcome. He has not had a recurrent stroke in over 6 years. Although medical treatment is generally considered the first choice for VBA stenosis, recurrent cerebral infarction occurs at a high rate in symptomatic lesions, and the prognosis is poor. In addition, the perioperative complication rate is not low, and there is no established method for evaluating perfusion of posterior circulation. The brain oximeter is already known to be useful in carotid artery (CA) revascularisation. In this report, we were able to perform a minimally invasive evaluation of blood flow in the posterior circulation using the brain oximeter which might be useful for surgical revascularisation not only in CA but also in VBA.

Safety, Pharmacokinetics and Pharmacodynamics of DS-1040, in Combination with Thrombectomy, in Japanese Patients with Acute Ischemic Stroke.

BACKGROUND AND OBJECTIVES: DS-1040 is a novel inhibitor of the activated form of thrombin-activatable fibrinolysis inhibitor that may have therapeutic potential in thromboembolic diseases, such as acute ischemic stroke (AIS) or pulmonary embolism. We undertook a Phase I clinical trial to investigate the safety, pharmacokinetics, and pharmacodynamics of DS-1040 in Japanese patients who were eligible for thrombectomy following AIS. METHODS: The trial enrolled patients with AIS due to large vessel occlusion, who were planned for thrombectomy within 8 h of symptom onset. Subjects were randomized to receive a single intravenous infusion of placebo or DS-1040 (0.6, 1.2, 2.4 or 4.8 mg) in a sequential-cohort design. The primary endpoints were the incidence of intracranial hemorrhage (ICH) and major extracranial bleeding within 36 and 96 h, respectively, of treatment initiation. Treatment-emergent adverse events (TEAEs) and pharmacokinetic/pharmacodynamic parameters were also assessed. RESULTS: Nine patients received placebo and 32 patients received DS-1040. There were no cases of symptomatic ICH or major extracranial bleeding with either placebo or DS-1040 after 36 and 96 h. One patient, who received DS-1040 0.6 mg, experienced a subarachnoid hemorrhage that was considered to be drug-related. Three patients died (2 placebo, 1 DS-1040), but no deaths were adjudicated as study drug-related. In vivo exposure to DS-1040 increased in proportion to dosage, but no clear dose-response relationship was seen for D-dimer levels and thrombin-activatable fibrinolysis inhibitor activity. CONCLUSIONS: Single doses of DS-1040 0.6-4.8 mg were well tolerated in Japanese patients with AIS undergoing thrombectomy. CLINICAL TRIAL REGISTRATION NUMBER: NCT03198715; JapicCTI-163164.

Effect of region-wide use of prehospital stroke triage scale on management of patients with acute stroke.

BACKGROUND: Prehospital stroke triage scales help with the decision to transport patients with suspected stroke to suitable hospitals. OBJECTIVE: To explore the effect of the region-wide use of the Japan Urgent Stroke Triage (JUST) score, which can predict several types of stroke: large vessel occlusion (LVO), intracranial hemorrhage (ICH), subarachnoid hemorrhage (SAH), and cerebral infarction other than LVO (CI). METHODS: We implemented the JUST score and conducted a retrospective and prospective multicenter cohort study at 13 centers in Hiroshima from April 1, 2018, to March 31, 2020. We investigated the success rate of the first request to the hospital, on-scene time, and transport time to hospital. We evaluated the door-to-puncture time, puncture-to-reperfusion time, and 90-day outcome among patients with final diagnoses of LVO. RESULTS: The cohort included 5141 patients (2735 before and 2406 after JUST score implementation). Before JUST score implementation, 1269 strokes (46.4%) occurred, including 140 LVO (5.1%), 394 ICH (14.4%), 120 SAH (4.4%), and 615 CI (22.5%). The JUST score was used in 1484 (61.7%) of the 2406 patients after implementation, which included 1267 (52.7%) cases of stroke (186 LVO (7.7%), 405 ICH (16.8%), 109 SAH (4.5%), and 567 CI (23.6%)). Success rate of the first request to the hospital significantly increased after JUST score implementation (76.3% vs 79.7%, p=0.004). JUST score implementation significantly shortened the door-to-puncture time (84 vs 73 min, p=0.03), but the prognosis remained unaltered among patients with acute LVO. CONCLUSIONS: Use of prehospital stroke triage scales improved prehospital management and preparation time of intervention among patients with acute stroke.

Near-Infrared Spectroscopy Might Help Prevent Onset of Cerebral Hyperperfusion Syndrome.

Cerebral hyperperfusion syndrome (CHS) is a rare but fatal perioperative complication after surgical correction of carotid stenosis. Despite numerous treatment options for preventing CHS, it does occur in some patients. We developed the outlet gate technique (OGT), in which the embolic balloon was deflated gradually in accordance with the ratio of oxygen saturation measured by a brain oximeter of the ipsilateral brain region to that in the contralateral region. Between June 2017 and May 2018, 39 patients with carotid stenosis underwent endovascular carotid revascularization procedures; of these, 20 underwent the procedure with the OGT. CBO was measured five times in those 20 patients: before the procedure, with the embolic protection device (EPD) on, with the EPD off, during the procedure, and after the procedure. Preventive treatment options were used more frequently in these patients, and although their surgical status seemed more complicated, perioperative complications were not increased. There were almost significant differences between CBO values except between those during and after the procedure with the OGT. This showed that the OGT allowed for stabilization of the CBO and thus has the potential to prevent CHS.

A Child with Paradoxical Cerebral Embolism in Whom Mechanical Thrombectomy Led to a Favorable Outcome.

Objective: We report a case of paradoxical cerebral embolism caused by patent foramen ovale (PFO) that was treated by the direct aspiration first pass technique (ADAPT). Case Presentation: The case involved a 12-year-old boy who had symptoms of dizziness and vomiting the day prior to being admitted to the emergency department. The following morning, consciousness disorder, dysarthria, and right paresis were observed, and he was transferred to our hospital. Computed tomography (CT) and magnetic resonance imaging (MRI) lead to the diagnosis of acute cerebral infarction due to basilar artery (BA) occlusion. Mechanical thrombectomy was performed, and Thrombolysis in Cerebral Infarction (TICI) 3 was obtained. Postoperatively, his consciousness was improved, but echocardiography revealed PFO. Percutaneous PFO closure was performed at our department of pediatric cardiology. Conclusion: For our patient with paradoxical cerebral embolism of the BA caused by PFO more than 6 hours after onset, mechanical thrombectomy with ADAPT using a Penumbra 5MAX ACE68 resulted in a good outcome.

[A Case of Giant Cerebral Aneurysm Treated with Multiple Sheaths Directly Punctured into the Carotid Artery].

When it is difficult to approach the brachial or femoral artery during endovascular surgery, an alternative approach is the direct puncture of the carotid artery. In this case of a giant cerebral aneurysm, we punctured the carotid artery directly and performed flow diverter stent placement and endosaccular coil embolization. Although the procedure required two thick access routes, it was performed after administering two antiplatelet drugs and an anticoagulant in order to achieve reliable hemostasis of the puncture sites after the operation. Direct common carotid artery puncture through a cervical skin incision is useful, because it ensures multiple access routes safely and provides secure hemostasis of the puncture sites.

Stent-assisted Coil Embolization to Treat Extracranial Carotid Artery Aneurysm 13 Years after Endarterectomy: A Case Report.

Development of extracranial carotid artery aneurysm (ECCA) after carotid endarterectomy (CEA) is a rare complication, occurring in connection with <1% of all CEAs. The main causes are infection, suture failure, and degeneration of arterial wall or patch. The traditional treatment has been operative repair, which can present a significant technical challenge owing to reoperative neck inflammation and potential cranial nerve injuries. Here, we report a case of successful stent-assisted coil embolization for right noninfectious ECCA. A 63-year-old female was admitted to our hospital for a 3-cm pulsating mass in her right midneck. Doppler examination and digital subtraction angiography revealed a large (15 mm) ECCA at the right common carotid artery (CCA). Thirteen years earlier, eversion CEA with patch angioplasty and abbreviation of the internal carotid artery (ICA) had been performed for a symptomatic 80% diameter stenosis with transient ischemic attack at another hospital. As the patient refused blood transfusion for religious reasons, we treated her with stent-assisted coil embolization, which achieved nearly complete obliteration of the aneurysm while preserving the parent artery patency. Three months after initial treatment, ultrasound revealed complete occlusion of the ECCA, but also showed stent shortening. Hence, we performed an additional stent placement so as to overlap the previous stent by 2.5 cm. Six months after initial treatment, carotid duplex ultrasound confirmed a good outcome. This procedure is an excellent choice for high-risk patients, and a larger case series is needed to establish this technique as the treatment of choice for ECCAs.

Midterm Follow-Up of Patients with Middle Meningeal Artery Embolization in Intractable Chronic Subdural Hematoma.

OBJECTIVE: A subset of patients with chronic subdural hematoma (CSDH) remains refractory to standard treatment with hematoma drainage by burr-hole craniotomy and irrigation. We recently reported the usefulness of middle meningeal artery (MMA) embolization for intractable CSDH in patients with multiple intractable risk factors. We present the midterm outcomes of MMA embolization in patients with intractable CSDHs. METHODS AND RESULTS: Seventeen consecutive patients (average age, 76.4 years; 12 men [71%]) underwent MMA embolization of CSDH from January 2014 to July 2017. Earlier interventions included embolization using N-butyl-2-cyanoacrylate (although trisacryl gelatin microspheres were used in recent cases), followed by burr-hole craniotomy and irrigation in all cases. None of the patients experienced perioperative complications or postoperative recurrence. The modified Rankin Scale scores, which were unfavorable at admission, improved significantly at discharge but were comparable to those at the time of hospitalization when measured during the follow-up period. Although the patients required rehospitalization at other departments for unrelated causes, none required rehospitalization in our department. CONCLUSIONS: Despite the known unfavorable outcomes of patients with intractable CSDHs, MMA embolization was not associated with recurrent CSDH or rehospitalization in our department in the current case series. MMA embolization should be considered a preferred therapeutic option for intractable CSDHs.

Endovascular Treatment for Aneurysmal Subarachnoid Hemorrhage with Neurogenic Pulmonary Edema in the Acute Stage.

AIM: Severe neurogenic pulmonary edema (NPE) can occur in a variety of brain insults, including subarachnoid hemorrhage (SAH), and severe case of NPE can cause devastating consequences. But the literature on the treatment strategy about aneurysmal SAH with NPE is very scant. We present that SAH patients with severe NPE, who were treated first by embolization of aneurysm followed by insertion of lumbar spinal drainage, had comparatively good outcome. MATERIAL AND METHODS: We present 12 consecutive cases of aneurysmal SAH with NPE in the acute stage, which were treated by endovascular treatment between April 2002 and December 2012. We classified the patients according to the Hunt and Hess grading system as follows: grade-3 (1 patient), grade-4 (4 patients), and grade-5 (7 patients). All patients needed respiratory management, with the assistance of a ventilator, and underwent endovascular treatment for the ruptured aneurysms within 72 hours from onset. For all the patients, immediately after the endovascular treatment, we performed lumbar spinal drainage. RESULTS: The pulmonary edema disappeared rapidly after respiratory management and endovascular treatment. The outcomes were as follows: good recovery (GR; 3 patients), moderate disability (MD; 4 patients), severe disability (SD; 3 patients), and death (D; 2 patients). Five patients (42%) developed pneumonia, and we postponed extubation until recovery from pneumonia. The cause for severe disability and death was symptomatic vasospasm and primary brain damage. No patients had rebleeding from ruptured aneurysms. CONCLUSION: Endovascular treatment for ruptured aneurysm and placement of lumbar spinal drainage is an excellent treatment option for severe SAH with NPE.

[Responding to Arterial Perforation during Endovascular Neurosurgery].

During endovascular neurosurgery, various devices, such as catheters, are passed through the intracranial arteries to access target vessels; the arteries can thereby be perforated. Even though such incidents are serious and should be dealt with appropriately, few case reports or standard procedures have been published. Herein, we report two cases of arterial perforation that occurred recently in our hospital. In the first case, the patient had been treated preoperatively using feeder occlusion of an arteriovenous malformation; the microcatheter perforated the feeder, which branched from the middle cerebral artery. The feeder and perforation site were occluded by injection of n-butyl 2-cyanoacrylate (NBCA) through the same microcatheter, and complete hemostasis was thereby achieved. The second case occurred during an embolization of the middle meningeal artery (MMA) to treat a refractory chronic subdural hematoma;the microcatheter perforated a branch of the MMA. Both the perforation and the artery were embolized using platinum coils and by injecting NBCA, and hemostasis was achieved. Considering the anatomical and pathological properties of the injured vessels, favorable results were achieved with appropriate intervention.

Primary pontine hemorrhage in the acute stage: clinical features and a proposed new simple scoring system.

BACKGROUND: It is important to evaluate the likelihood of fatality in patients with acute primary pontine hemorrhage (PPH) in emergency departments. We aimed to evaluate the clinical symptoms and computed tomography findings of PPH to develop a simple grading scale for predicting the mortality of PPH. METHODS: Records of 101 consecutive patients admitted to our hospital with acute PPH between June 1, 2006, and January 31, 2014, were retrospectively reviewed. Independent predictors of 30-day mortality were identified by univariate and multivariate logistic regression analyses. A simple and easy clinical score (PPH score) was developed from independent factors to predict mortality in acute PPH. The PPH score was compared with the established intracerebral hemorrhage (ICH) score, which served as the reference scoring system. RESULTS: Overall mortality rate 30 days after onset was 58.4% (59 of 101). Factors independently associated with 30-day mortality were Glasgow Coma Scale (GCS) score of 6 or less (P = .0051), absence of pupillary light reflex (P = .0003), and blood glucose of 180 mg/dL or greater (P = .0312). The PPH score was the sum of independent factors, which were assigned 1 point each. The area under the receiver operating characteristic curve for predicting 30-day mortality was .90 (95% confidence interval [CI], .84-.95) for PPH score and .86 (95% CI, .78-.93) for ICH score. CONCLUSIONS: GCS score of 6 or less, absence of pupillary light reflex, and plasma glucose of 10 mmol/L or greater are independent mortality predictors of PPH. The PPH score is a simple and reliable clinical grading scale for predicting 30-day mortality.

[Ischemic complications of anterior choroidal artery aneurysm treatment].

Ischemic stroke of the anterior choroidal artery(AChA)is the most common and serious complication after AChA aneurysm treatment. The purpose of this study was to retrospectively evaluate and compare the treatment-related ischemic complications after surgical clipping and endovascular coiling of AChA aneurysms.
Between June 2006 and March 2013, 32 patients with 34 AChA aneurysms were treated in our hospital by surgical clipping or endovascular coiling. There were 12 cases of ruptured aneurysms, seven cases of unruptured aneurysms, and 15 cases of incidentally identified unruptured aneurysms. Of the 34 aneurysms, 19 were managed with surgical clipping and 15 were managed with endovascular coiling. No rebleeding or retreatment occurred in any case during 4-84 months(median, 25 months)of follow-up, and no significant differences in clinical outcome were seen between clipping and coiling cases. Although there were four cases(11.8%;surgical clipping in three;endovascular coiling in one)of postoperative AChA infarction, we believe that we preserved the blood flow of the AChA during the procedure. The occurrence of subarachnoid hemorrhage and premature rupture during surgical clipping were significantly correlated with AChA infarction.

[Embolization of the feeding artery of a meningioma with dangerous vascular anastomosis between the middle meningeal artery and the ophthalmic artery].

Preoperative embolization of intracranial meningioma has been applied to reduce intraoperative blood loss and to facilitate microsurgical removal of a tumor. It is well known that one of the reasons of the neurological risk of embolization is due to dangerous anastomosis between the extracranial and the intracranial arteries. One of the most known and dangerous case of anastomosis is between the middle meningeal artery to the ophthalmic artery. A 48-year-old woman underwent preoperative embolization of a large right middle cranial fossa meningioma. The right external carotid angiogram showed that the tumor was fed by the right middle meningeal artery and there was no branch to the right orbital region. The right internal carotid angiogram showed that the right ophthalmic artery originated from the right internal carotid artery and there was no branch to the tumor. The selective angiogram of the anterior branch of the middle meningeal artery disclosed the anastomosis to the right ophthalmic artery. Following embolization of the anterior branch of the middle meningeal artery, the patient underwent embolization of the main feeding branch of the meningioma. She successfully underwent surgical removal of the tumor without any blood transfusion and was discharged without neurological deficit. In addition, to avoid complication in embolization of the feeding artery of a skull base meningioma, clinicians must be aware of the dangerous anastomosis between the middle meningeal artery and the ophthalmic artery, even if conventional external and internal carotid angiograms do not show any anastomosis.

[Pyoktanin blue injection for resection of cystic brain tumor: a case report].

Pyoktanin blue is an agent that is often used during STA-MCA anastomosis. In this report, we inject it into a cystic tumor for complete resection, and we report its usefulness. The patient was a 57-year-old female. She suffered from progressive cerebellar ataxia. CT and MR showed a cystic metastatic tumor at the right cerebellar hemisphere, 40mm in diameter. Craniotomy was performed, 5cm in diameter, using the right suboccipital approach. After peeling off the tumor from the surface layer of the brain, we injected diluted pyoktanin blue into the tumor to dye the inside wall. After that, the tumor was peeled off completely without exposing the dyed inside wall. We sometimes find it difficult to distinguish tumor from brain if there is tearing of the tumor wall. Tearing of the tumor can be prevented by injecting pyoktanin blue into it, and making the inside wall visible. Using this procedure, we think a tumor can be resected without residual tumor or damage to the brain. Although we have used this method only a few times, we think it is an easy and useful technique to inject pyoktanin blue into a cystic tumor during its resection.