Surgical treatment of solid hemangioblastomas of the posterior fossa: A report of 28 cases

Preoperative embolization and microsurgical resection of a cerebellar hemangioblastoma: embolization goals and technical nuances of the approaches. Illustrative case

BACKGROUND

Resection remains the optimal treatment for hemangioblastomas, highly vascular tumors commonly located in the cerebellum or spinal cord. Preoperative embolization can be used with caution to reduce intraoperative blood loss and promote gross-total resection while reducing neurological morbidity.

OBSERVATIONS

The authors report a case of a 44-year-old male who presented with worsening dizziness, gait imbalance, and diplopia. Imaging revealed a large vascular cerebellar mass with brainstem compression and hydrocephalus, concerning for hemangioblastoma. The patient underwent preoperative embolization of the main arterial supply from the right superior cerebellar artery, which devascularized the tumor and reduced the early venous shunting, followed by gross-total resection of the tumor. Preoperative embolization helped to facilitate safe microsurgical resection because this main arterial supply was deep to the planned surgical approach, and the Onyx cast served as a landmark of the dorsal midbrain and remaining arterial supply. This resulted in minimal intraoperative blood loss. At 2-year follow-up, the patient's diplopia and vertigo had resolved, and his gait continues to improve.

LESSONS

Despite controversy regarding the use of preoperative embolization for hemangioblastoma resection, the authors emphasize its safety and utility during resection of a large cerebellar hemangioblastoma. Onyx embolization provided benefit in both reducing the tumor blood supply and serving as intraoperative visual guidance.

Multimodal management of giant solid hemangioblastomas in two patients with preoperative embolization

Background

Hemangioblastomas are benign vascular neoplasms, World Health Organization grade I, with the most frequent location in the cerebellum. Complete microsurgical resection can be a challenge due to excessive bleeding, which is why preoperative embolization takes importance.

Case Description

Two clinical cases are presented, a 25-year-old woman and a 75-year-old man, who presented with intracranial hypertension symptoms due to obstructive hydrocephalus; a ventriculoperitoneal shunt was placed in both cases; in addition, they presented with cerebellar signs. Both underwent embolization with ethylene vinyl alcohol copolymer, with blood flow reduction. After that, they underwent microsurgical resection within the 1st-week post embolization, obtaining, in both cases, gross total resection without hemodynamic complications, with clinical improvement and good surgical outcome. It is worth mentioning that surgical management is the gold standard that allows a suitable surgical approach, like in our patients, for which a lateral suboccipital craniotomy was performed.

Conclusion

Solid hemangioblastomas are less frequent than their cystic counterparts. The treatment is the surgical resection, which is a challenge and always has to be considered as an arteriovenous malformation in the surgical planning, including preoperative embolization to reduce perioperative morbidity and mortality and get good outcomes.

Assessing the efficacy and safety of hemangioblastoma embolization: A comprehensive systematic review and meta-analysis

BACKGROUND

Hemangioblastomas (HBs) are highly vascular tumors linked to substantial morbidity and mortality. Recently, interventional neuroradiology has evolved rapidly, spurring interest in preoperative embolization as a possible HB treatment.

PURPOSE

This study evaluates the effectiveness and safety of preoperative embolization in managing HB.

METHODS

Adhering to PRISMA guidelines, this meta-analysis considered randomized and nonrandomized studies meeting specific criteria, encompassing intracranial HB and preoperative embolization. Primary outcomes were preoperative embolization efficacy and safety. Complications were classified as major (cerebellar ischemia, ischemic strokes, intratumoral hemorrhage, subarachnoid hemorrhage) and minor (transient nystagmus, slight facial nerve palsy, nausea, transient dysarthria, hemiparesis, hemisensory impairment, thrombotic complications, extravasation).

RESULTS

Thirteen studies involving 166 patients with preoperative embolization before HB resection were included. Two studies using the Glasgow Outcome Scale (GOS) showed 5 patients with good recovery, 6 with moderate disability, and 3 with severe disability. Major complications occurred in 1% (95% CI: 0% to 3%), and minor complications occurred in 1% (95% CI: 0% to 4%). Intraoperative blood loss during resection was estimated at 464.29 ml (95% CI: 350.63 ml to 614.80 ml).

CONCLUSION

Preoperative embolization holds promise in reducing intraoperative bleeding risk in neurosurgical intracranial HB treatment, primarily due to its low complication rates. Nonetheless, additional research and larger-scale studies are essential to establish its long-term efficacy and safety. These findings highlight preoperative embolization as a valuable tool for HB management, potentially enhancing future patient outcomes.

Handling Severe Intraoperative Hemorrhage and Avoiding Iatrogenic Stroke During Brain Tumor Surgery: Techniques for Prevention of Hemorrhagic and Ischemic Complications

BACKGROUND

Nationwide databases show that iatrogenic stroke and postoperative hematoma are among the commonest complications in brain tumor surgery, with a 10-year incidence of 16.3/1000 and 10.3/1000, respectively. However, techniques for handling severe intraoperative hemorrhage and dissecting, preserving, or selectively obliterating vessels traversing the tumor are sparse in the literature.

METHODS

Records of the senior author's intraoperative techniques during severe haemorrhage and vessel preservation were reviewed and analyzed. Intraoperative media demonstrations of key techniques were collected and edited. In parallel, a literature search investigating technique description in handling severe intraoperative hemorrhage and vessel preservation in tumor surgery was undertaken. Histologic, anesthetic, and pharmacologic prerequisites of significant hemorrhagic complications and hemostasis were analyzed.

RESULTS

The senior author's techniques for arterial and venous skeletonization, temporary clipping with cognitive or motor mapping, and ION monitoring were categorized. Vessels interfacing with tumor are labeled intraoperatively as supplying/draining the tumor, or traversing en passant, while supplying/draining functional neural tissue. Intraoperative techniques of differentiation were analyzed and illustrated. Literature search found 2 vascular-related complication domains in tumor surgery: perioperative management of excessively vascular intraparenchymal tumors and lack of intraoperative techniques and decision processes for dissecting and preserving vessels interfacing or traversing tumors.

CONCLUSIONS

Literature searches showed a dearth of complication-avoidance techniques in tumor-related iatrogenic stroke, despite its high prevalence. A detailed preoperative and intraoperative decision process was provided along with a series of case illustrations and intraoperative videos showing the techniques required to reduce intraoperative stroke and associated morbidity addressing a void in complication avoidance of tumor surgery.

Supratentorial hemangioblastoma: A rare case report and literature review

Hemangioblastomas are rare and benign tumors of the central nervous system. They account for 1.5%-2.5% of all intracranial tumors and have an incidence of 3.2%. The resemblance of hemangioblastomas to other tumors renders preoperative diagnosis and management challenging. Herein, we report a case of a supratentorial hemangioblastoma accompanied by extensive reactive gliosis and diagnosed through magnetic resonance imaging. In addition, we review the relevant literature.

Successful preoperative embolization of a cystic-solid variant of cerebellopontine angle hemangioblastoma

Tumors of the cerebellopontine angle (CPA) represent an heterogeneous group which can arise extradural, intradural-extraaxial or intraaxial compartment. Hemangioblastomas of the cerebellopontine angle (CPA) are extremely rare. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the gold-standard radiological imaging modalities used in characterizing the lesion's features, and its relationship with the surrounding structures. They are vascular lesions and may cause profuse bleeding intraoperatively, that is why angiography remains a crucial diagnostic and therapeutic tool, by reducing both the presurgical differential diagnosis, as well as the intraoperative bleeding by providing capability of embolization of this vascular tumor. We present the case of a 65 year old patient with a cystic-solid variety of HMB at the right CPA, which was successfully treated by a combination of an endovascular preoperative embolization and surgery without major complications or neurological deficits.

Tool-Tissue Forces in Hemangioblastoma Surgery

OBJECTIVE

Surgical resection of intracranial hemangioblastoma poses technical challenges that may be difficult to impart to trainees. Here, we introduce knowledge of tool-tissue forces in Newton (N), observed during hemangioblastoma surgery.

METHODS

Seven surgeons (2 groups: trainees and mentor), with mentor (n = 1) and trainees (n = 6, PGY 1-6 including clinical fellowship), participated in 6 intracranial hemangioblastoma surgeries. Using sensorized bipolar forceps, we evaluated tool-tissue force profiles of 5 predetermined surgical tasks: 1) dissection, 2) coagulation, 3) retracting, 4) pulling, and 5) manipulating. Force profile for each trial included force duration, average, maximum, minimum, range, standard deviation (SD), and correlation coefficient. Force errors including unsuccessful trial bleeding or incomplete were compared between surgeons and with successful trials.

RESULTS

Force data from 718 trials were collected. The mean (standard deviation) of force used in all surgical tasks and across all surgical levels was 0.20 ± 0.17 N. The forces exerted by trainee surgeons were significantly lower than those of the mentor (0.15 vs. 0.24; P < 0.0001). A total of 18 (4.5%) trials were unsuccessful, 4 of them being unsuccessful trial-bleeding and the rest, unsuccessful trial-incomplete. The force in unsuccessful trial-bleeding was higher than successful trials (0.3 [0.09] vs. 0.17 [0.11]; P = 0.0401). Toward the end of surgery, higher force was observed (0.17 vs. 0.20; P < 0.0001).

CONCLUSIONS

The quantification of tool-tissue forces during hemangioblastoma surgery with feedback to the surgeon, could well enhance surgical training and allow avoidance of bleeding associated with high force error.

Treatment Strategy for Giant Solid Hemangioblastomas in the Posterior Fossa: A Retrospective Review of 13 Consecutive Cases

OBJECTIVE

To analyze radiologic characteristics, treatment strategy, and treatment outcomes of posterior fossa giant solid hemangioblastomas (GSHBs; ≥4 cm in maximum diameter).

METHODS

We performed a retrospective study of 13 consecutive patients (9 male and 4 female patients; mean age, 57.5 ± 13.3 years; range, 24-76 years) with GSHB who underwent surgical resection at a single institution between 2002 and 2018. The median follow-up was 33 months (range, 12-120 months). For each patient, neuroimaging findings, operative record, and treatment outcome were reviewed.

RESULTS

Seven tumors (53.8%) were located within cerebellar hemispheres, 4 (30.8%) in proximity to the brainstem, 1 (7.7%) within the cerebellar vermis, and 1 (7.7%) in the cerebellopontine angle. The mean maximum diameter was 4.8 ± 0.8 cm (range, 4.0-6.7 cm). Gross total resection was achieved in 11 patients (84.6%), and near-total resection in 2 patients (15.4%). Surgical complications occurred in 5 patients (38.5%); persistent neurologic deficits occurred in 2 patients (15.4%). Estimated progression-free survival after surgery was 92.3%, 80.8%, and 80.8% at 1, 5, and 10 years, respectively, whereas the estimated 1-year, 5-year, and 10-year overall survival was 100%, 90%, and 90%, respectively.

CONCLUSIONS

GSHBs are surgically challenging. The current study shows that favorable outcome can be achieved for GSHBs in the cerebellar hemispheres and vermis. For those involving the brainstem, planned near-total resection or subtotal resection in a piecemeal fashion can be attempted if en bloc resection is judged to be infeasible, and further intervention can be considered as needed.

Surgical Outcome of Large Solid Posterior Fossa Hemangioblastoma without Preoperative Embolization

BACKGROUND

 Large solid hemangioblastoma in the posterior fossa has an abundant blood supply as an arteriovenous malformation. The presence of adjacent vital neurovascular structures makes them vulnerable and difficult to operate. Complete surgical resection is always a challenge to the neurosurgeon.

MATERIAL AND METHOD

 We share the surgical difficulties and outcome in this case series of large solid hemangioblastomas without preoperative embolization as an adjunct. This study included five patients (three men and two women, with a mean age of 42.2 years). Preoperative embolization was attempted in one patient but was unsuccessful. All the patients have headache (100%) and ataxia (100%) as an initial symptom. A ventriculoperitoneal shunt was inserted in one case before definite surgery due to obstructive hydrocephalus. The surgical outcome was measured using the Karnofsky Performance Status (KPS) score.

RESULT

 The tumor was excised completely in all the cases. No intra- and postoperative morbidity occurred in four patients; one patient developed transient lower cranial nerve palsy. Mean blood loss was 235 mL, and no intraoperative blood transfusion was needed in any case. The mean follow-up period was 14.2 months. The mean KPS score at last follow-up was 80.One patient had a KPS score of 60.

CONCLUSION

 Our treatment strategy is of circumferential dissection followed by en bloc excision, which is the optimal treatment of large solid hemangioblastoma. The use of adjuncts as color duplex sonography and indocyanine green video angiography may help complete tumor excision with a lesser risk of complication. Preoperative embolization may not be needed to resect large solid posterior fossa hemangioblastoma, including those at the cerebellopontine angle location.

MicroRNA-4458 Regulates PD-L1 Expression to Enhance Anti-tumor Immunity in NSCLC via Targeting STAT3

MicroRNA-4458 (miR-4458) has been reported to be associated with several cancers including non-small-cell lung cancer (NSCLC), while its role in tumor immunity remains unclear. The purpose of the current research was to explore the anti-tumor immunity of miR-4458 in NSCLC. The results showed that the expression level of miR-4458 decreased and STAT3 increased in NSCLC tissues and cells. For in vitro experiments, miR-4458 mimics suppressed cell proliferation and decreased the expression level of PD-L1. Moreover, STAT3 was confirmed as a target gene of miR-4458. Upregulation of STAT3 level ameliorated the inhibitive effects of miR-4458 on cells proliferation and PD-L1 expression in cells. For in vivo studies, overexpression of miR-4458 hindered tumor growth, decreased the proportion of PD-1⁺ T cells, the expression of PD-L1 and IL-10, upregulated the proportion of CD4⁺ T, CD8⁺ T cells as well as the expression of IFN-γ and IL-2, which were all reversed by overexpression of STAT3, and the effects of STAT3 were counteracted after knockdown of PD-L1. MiR-4458 overexpression enhanced anti-tumor immunity via targeting STAT3 to block the PD-L1/PD-1 pathway.

Synchronous Presentation of Rare Brain Tumors in Von Hippel-Lindau Syndrome

Von Hippel-Lindau (VHL) disease is a heritable cancer syndrome in which benign and malignant tumors and/or cysts develop throughout the central nervous system (CNS) and visceral organs. The disease results from mutations in the VHL tumor suppressor gene located on chromosome 3 (3p25-26). A majority of individuals (60-80%) with VHL disease will develop CNS hemangioblastomas (HMG). Endolymphatic sac tumor (ELST) is an uncommon, locally aggressive tumor located in the medial and posterior petrosal bone region. Its diagnosis is based on clinical, radiological, and pathological correlation, and it can occur in the setting of VHL in up to 10-15% of individuals. We describe a 17-year-old male who presented with a chief complaint of hearing loss. Brain and spine Magnetic Resonance Imaging documented the presence of an expansive lesion in the left cerebellar hemisphere, compatible with HMG in association with a second cerebellopontine lesion compatible with ELST. The peculiarity of the reported case is due to the simultaneous presence of two typical characteristics of VHL, which led to performing comprehensive genetic testing, thus allowing for the diagnosis of VHL. Furthermore, ELST is rare before the fourth decade of life. Early detection of these tumors plays a key role in the optimal management of this condition.

Selection of surgical approach for cerebellar hemangioblastomas based on venous drainage patterns

Cerebellar hemangioblastomas remain surgically challenging because of the narrow, deep surgical corridors and tumor hypervascularity. Various surgical approaches are used according to the location, but optimal approaches have not been established. We propose a system of surgical approaches based on the venous drainage systems to facilitate surgical planning and achieve acceptable neurological outcomes. Cerebellar hemangioblastomas were divided into five types based on the main drainage systems: suboccipital hemangioblastomas draining to the transverse sinus (TS) or torcula, tentorial hemangioblastomas draining to the tentorial sinus or straight sinus, petrosal hemangioblastomas draining to the superior petrosal sinus (SPS), quadrigeminal hemangioblastomas draining to the galenic system, and tonsillar hemangioblastomas draining to the TS or torcula in conjunction with jugular bulb or SPS. Microsurgical approaches and patient outcome were retrospectively reviewed according to this classification. This study included 17 patients who underwent 21 operations for resection of 19 cerebellar hemangioblastomas, classified into 9 suboccipital, 4 tentorial, 2 petrosal, 2 quadrigeminal, and 2 tonsillar. Standard suboccipital craniotomies were utilized for suboccipital hemangioblastomas, the occipital transtentorial approach (OTA), and supracerebellar infratentorial approach for tentorial hemangioblastomas, the retrosigmoid approach for petrosal hemangioblastomas, OTA for quadrigeminal hemangioblastomas, and midline suboccipital approach for tonsillar hemangioblastomas. Gross total resection was achieved in all patients except one. Two patients with large hemangioblastomas (tonsillar and quadrigeminal) required second-stage operation which finally achieved gross total removal. No single approach had a significantly higher incidence of postoperative neurological deficits. Selection of the optimum surgical approach for cerebellar hemangioblastomas was successful based on the main drainage systems. Understanding of tumor growth and extension with respect to the venous drainage system is critical to select the appropriate surgical approach.

Solid Component Volume as a Proxy to Identify Distinct Hemangioblastoma Populations

BACKGROUND

Posterior fossa hemangioblastomas usually consist of a small solid nodule with a large cyst, while more rarely they present as a large solid mass with a small or absent cyst, which can be surgically challenging. We sought to investigate the potential existence of multiple distinct hemangioblastoma populations using tumor volumetric data as an indicator.

METHODS

We conducted a retrospective review of surgically treated hemangioblastomas between 2005 and 2019 in our unit, including clinical notes, preoperative magnetic resonance imaging volumetric analysis of the solid component of the tumor, and pathology. Finite Gaussian mixture modeling was applied on the solid component volume dataset to identify potential underlying Gaussian distributions with their associated characteristics. Nonparametric Mann-Whitney U tests were used to investigate significance of differences (P < 0.05) in solid component volume and different variables (Von Hippel-Lindau disease, extent of resection, outcome).

RESULTS

A total of 68 consecutive patients were included. Solid component volumes followed a multimodal distribution (median = 1287 mm³, interquartile range of 3428 mm³). The best-fit finite Gaussian mixture modeling model identified 3 statistically significant different (P = 0.001) potential mixture components: X₁ (219 ± 187 mm³)_, X₂ (2686 ± 1299 mm³), and X₃ (10,800 ± 5514 mm³). The second-best model detected 2 significantly different (P = 9.99e^-08) mixture components Y₁ (222 ± 189 mm³) and Y₂ (5391 ± 5094 mm³). A significant difference in solid component volume was found between patients with favorable and unfavorable outcome (P = 0.002).

CONCLUSIONS

This study has shown preliminary evidence that large solid hemangioblastomas may constitute a completely distinct population, rather than a variant of one large group of hemangioblastomas.

Case of Clear Cell Ependymoma Successfully Treated with Preoperative Embolization

Objective

Clear cell ependymoma (CCE) is known to be very similar to hemangioblastoma (HB) in regards to neuroimaging and histopathology. We report a rare case of CCE in which successfully underwent preoperative embolization with a prior diagnosis of HB.

Case Presentation

A 58-year-old woman presented with vertigo for several months. MRI showed the right cerebellar tumor mimicking solid HB. DSA revealed the hypervascular tumor supplied by branches of the posterior inferior cerebellar artery (PICA). To reduce intraoperative bleeding, preoperative embolization was performed using n-butyl-2-cyanoacrylate (NBCA). A flow-guided microcatheter was guided to the proper feeders, and diluted NBCA was injected. Sufficient devascularization was achieved. The tumor was totally resected with minimal blood loss the next day. Postoperative pathological diagnosis was CCE.

Conclusion

This is the first report that preoperative embolization was performed to CCE with careful techniques and recent advanced devices. Since CCE has a poorer prognosis, preoperative embolization for safety total resection may be more important.

Safety and efficacy of surgical treatment for brainstem hemangioblastoma: a meta-analysis

Brainstem hemangioblastomas are benign, highly vascular tumors located in the mesencephalon, pons, and medulla oblongata. Although surgical resection is currently considered the main therapeutic option for symptomatic lesions, evidence supporting the application of microsurgery has not been systematically assessed. This meta-analysis aims to evaluate the safety and efficacy of surgical treatment for brainstem hemangioblastomas. A comprehensive search of the PubMed, Embase, and Web of Science databases was performed to identify all English language publications reporting the outcomes of surgical treatment for brainstem hemangioblastomas. Studies from January 1990 to July 2019 with ≥ 10 cases were included. We analyzed the surgical outcomes, including gross total resection, mortality, neurological morbidity, and functional outcome according to the McCormick Scale or Karnofsky Performance Scale. Thirteen studies with 473 cases were included. The pooled proportion of gross total resection was 98% (95% confidence interval (CI), 94-100%). Overall mortality and neurological morbidity were 4 (95% CI, 2-6%) and 13% (95% CI, 7-20%), respectively. Favorable functional outcomes at the last follow-up were achieved in 85% (95% CI, 78-92%) of all patients. Improved or stable functional outcomes at long-term follow-up were achieved in 94% (95% CI, 89-97%) of patients. This meta-analysis revealed that surgical treatment for brainstem hemangioblastomas is technically feasible and effective with lasting patient benefits and cure.

Cystic-solid hemangioblastoma at the cerebellopontine angle: A case report

RATIONALE

Hemangioblastomas (HMGs) originating from the cerebellopontine angle (CPA) are extremely uncommon. Nevertheless, the cystic-solid form of this lesion at the above location is even rarer.

PATIENT CONCERNS

We present a 31-years old male with a right ear hearing loss of 3 months duration. He did not experience earache or discharge before the hearing loss. He; however, experienced visual acuity and dizziness. General physical examination did not yield much.

DIAGNOSES

Computed tomography and magnetic resonance imaging revealed a cystic-solid mass at right CPA. We initial misdiagnosed the lesion as an acoustic neuroma with cystic changes. Immunohistochemistry studies revealed HMG.

INTERVENTIONS

The lesion was total surgical resection via the retro-sigmoid approach.

OUTCOMES

The patient's symptomatology resolved after the surgery. Two years follow-up show no recurrence of the lesion and the patient is well.

LESIONS

Identification of feeding arteries and electro-coagulating them during the operation minimized intraoperative bleeding. The tumor should usually be dissected out whole and not piece meal fashion. Pre-operative CTA is very useful in outlining the vasculature of the tumor.

Growth rate and fate of untreated hemangioblastomas: clinical assessment of the experience of a single institution

BACKGROUND

The growth rate and natural history of untreated hemangioblastomas remain unclear. This study investigated the natural history of untreated intracranial hemangioblastomas and predictors of tumor growth using volumetric assessment.

METHOD

This study retrospectively enrolled 31 patients with untreated hemangioblastomas between 2004 and 2017 who were followed up for at least 12 months. The 31 patients had a total of 52 hemangioblastomas.

RESULTS

The 31 patients included 11 (35.5%) men and 20 (64.5%) women, of mean age 42.5 years. Seventeen (54.8%) patients were genetically diagnosed with Von Hippel-Lindau (VHL) disease. Of the 52 lesions, 33 (63.5%) grew during the follow-up period, whereas 19 (36.5%) remained stable. Overall mean actual growth rate (AGR) was 1.94 cm³/year, 2.38 cm³/year in the VHL and 1.79 cm³/year in the non-VHL group (p = 0.31). Overall mean relative growth rate (RGR) was 21%/year, 26%/year in the VHL and 19%/year in the non-VHL group. Time to 50% treatment probability was 34 months. The 1, 3, 5, and 7-year treatment probabilities were 11.5%, 50.1%, 52.7%, and 73%, respectively. The presence of only symptomatic lesions was significantly predictive of the growth of intracranial hemangioblastoma (odds ratio: 5.0, p = 0.02).

CONCLUSION

The overall growth rate of intracranial hemangioblastoma was faster than that of other benign intracranial tumors, with symptomatic lesions being the only meaningful predictor of tumor growth. Because of their rapid growth rate and high probability of treatment, a wait and scan management strategy should be carefully applied to intracranial hemangioblastomas.

A Rare Case of Giant Solid Hemangioblastoma Accompanied with Hemophilia Type A

The surgical removal of giant solid hemangioblastoma involves a high risk of perioperative bleeding and requires attentive hemostasis. Here, we present a case of a giant solid hemangioblastoma accompanied with hemophilia which was previously undiagnosed. A 35-year-old man without any past medical history was admitted with diplopia and ocular motility disorder. computed tomography (CT) and magnetic resonance imaging (MRI) revealed obstructive hydrocephalus and a solid giant tumor of more than 4.0 cm in diameter in the right cerebellopontine angle (CPA). Hemangioblastoma was suspected on cerebral angiography. After ventriculoperitoneal shunt for obstructive hydrocephalus, oozing from the skin incision continued for several days. Hemophilia type A was diagnosed based on the result of laboratory blood coagulability examination. Supplemental administration of factor VIII and coil embolization of the feeding arteries of the lesion on the CPA were performed, and the tumor was subtotally resected without hemorrhagic complications. The histopathological diagnosis was hemangioblastoma. We report this case to emphasize the importance not to overlook previously undiagnosed coagulopathy before surgical excision of hemangioblastoma. And, with appropriate perioperative management for coagulopathy, surgical treatment involving a high risk of perioperative bleeding can be safely undertaken.

The usefulness of indocyanine green during surgery for hypervascular posterior fossa tumors

BACKGROUND

Cerebral hemangioblastomas are benign tumors with abundant blood flow that occur mainly in the posterior fossa. Tumor removal en bloc is important in surgical treatment because of the risk of bleeding; however, it is actually rather difficult in practice. Therefore, we propose a surgical strategy for visualizing hypervascular tumors of the posterior fossa utilizing indocyanine green (ICG).

CASE DESCRIPTION

Case 1 involved a 48-year-old male with a history of von Hippel-Lindau (VHL) disease. Magnetic resonance imaging (MRI) revealed a solid tumor measuring 3.0 cm in diameter in the right cerebellopontine angle. We performed surgery because the tumor was pressing against the brainstem. Surgery was performed via the posterior subtemporal transtentorial approach in order to visualize the feeding artery and draining vein intraoperatively. The vessels were confirmed by ICG and the tumor was removed en bloc. Case 2 involved a 30-year-old woman. Signs of increased intracranial pressure were noted, and an MRI revealed a solid tumor 3.5 cm in diameter in the left cerebellar hemisphere. Surgery was performed via the midline suboccipital approach. Similarly, we confirmed the vessels using ICG and the tumor was removed en bloc.

CONCLUSIONS

For hypervascular tumors of the posterior fossa, preoperative image assessment is important. Furthermore, the use of ICG during surgery is advantageous for surgical strategies where the feeding arteries and draining veins exist superficially in the operative field and are therefore easier to remove en bloc.