Hemangiopericytoma of the cerebellopontine angle: a case report and review of the literature

Skull base hemangiopericytomas

OBJECTIVE

To retrospectively evaluate the clinical outcome of six patients with skull base hemangiopericytomas (HPCs) and that of a cohort of 37 similar patients identified by a systematic review of the literature.

METHODS

The series constitutes of three men and three women with newly diagnosed skull base HPC who underwent multimodal treatment including surgery, external beam radiotherapy (EBRT) and pre-operative embolization. Furthermore, a systematic review off the literature identified 37 reports of primarily intracranial skull base HPCs.

RESULTS

Four patients had a gross total resection (GTR) and two patients had a near total resection. Five patients were referred for adjuvant EBRT with a survival ranging from 15 to 47 months. All patients had an excellent outcome and resumed their previous activities. Literature review identified 37 additional patients with skull base HPC. Altogether, tumors were unevenly distributed above and below tentorium. GTR was achieved in half the patients, and 72.1% were referred to EBRT. Out of 37 reported patients in the literature, survival longer than 1 year was described in only 24. Within the combined cohort including the present series, survival was 83.6 months.

CONCLUSIONS

The present series shows that a radical resection of HPC can be achieved under the difficult anatomical conditions of skull base surgery. Pre-operative arterial embolization may be instrumental to maintain a clear visual field and prevent excessive blood loss. Finally, the results of the present cohort suggest that EBRT may be useful for local growth control, as an effective palliative measure for skull base HPCs.

Computed tomographic imaging of meningiomas

Although magnetic resonance imaging (MRI) has surpassed computerized tomography (CT) as the imaging modality of choice, there are certain instances when CT should be a preoperative requisite for meningioma surgical resection. Given its superior bone definition and the propensity for meningiomas to invade bone (as evidenced by hyperostosis on imaging), CT can be extremely helpful to the surgeon when planning and evaluating postoperatively the extent of bone removal during tumor resection. Advances in CT imaging also allow for visualization of the adjacent arterial and venous vasculature to determine feasibility of resection and likelihood of adjuvant treatments such as radiosurgery to a tumor residuum. For skull base tumors high-resolution CT imaging as part of the standard neuronavigation sequences can help evaluate bony anatomy and planning of surgical approaches, in particular for cranial base tumors. Finally, 3D-CT imaging is important in the design of cranial prostheses, which may be required to repair defects as a result of resection.

The Importance of STAT6 in a Schwannoma-like Grade III Solitary Fibrous Tumor/Hemangiopericytoma Located in the Cerebellopontine Angle and Meckel's Cave

BACKGROUND

Hemangiopericytoma (HPC) is a rare mesenchymal tumor of the brain that occurs in the central nervous system as a solitary fibrous tumor. Surgical treatment of HPC is known to be beneficial, but results on the role of complete resection and adjuvant radiation are conflicting. However, it is often difficult to detect a central nervous system solitary fibrous tumor/HPC before surgery. We describe a presumed left trigeminal schwannoma that was histopathologically shown to be an HPC.

CASE DESCRIPTION

A 65-year-old man presented with paresthesia of the second and third branches of the left trigeminal nerve. Magnetic resonance imaging showed a tumoral lesion in the left cerebellopontine angle and Meckel's cave. We suspected a schwannoma and performed surgery, which resulted in only a partial resection because of tumor bleeding and unexpected intraoperative histologic findings. We could not achieve a definitive diagnosis. However, we observed local recurrence and disseminated lesions 5 and 6.5 years later, respectively. We performed a second surgery and were able to definitively diagnose the lesion as a grade III HPC based on the positive expression of STAT6 during immunostaining.

CONCLUSIONS

As solitary fibrous tumor/HPC requires gross total resection for effective resolution, it is imperative to consider it in the differential diagnoses of similar tumors. If an unusual pathologic image is found, we recommend rapid immunostaining for STAT6 to reach a definitive conclusion regarding the tumor type. This case highlights the importance of considering HPC when screening or diagnosing central nervous system lesions, especially in this rare location.

Nervous System Hemangiopericytoma

The management of patients harboring central nervous system (CNS) hemangiopericytomas (HPCs) is a partially answered challenge. These are rare locally aggressive lesions, with potential for local recurrence, distal neural metastasis (DNM), and extraneural metastasis (ENM). Resection, when feasible, remains the initial treatment option, providing histological diagnosis and immediate relief of tumor-related mass effect. Patients receiving surgery alone or surgery and external beam radiotherapy (EBRT) show improved overall survival (OS) and progression-free survival as compared to those undergoing a biopsy alone (p = 0.01 and p = 0.02, respectively). Yet, in many instances, patient and tumor-related parameters preclude complete resection. EBRT or stereotactic radiosurgery (SRS) shares a significant role in achieving local tumor control, not shown to impact OS in HPC patients. The benefits of SRS/EBRT are clearly limited to improved local tumor volume control and neurologic function, not affecting DNM or ENM development. SRS provides acceptable rates of local tumor volume control coupled with treatment safety and a patient-friendly apparatus and procedure. Single-session SRS is most effective for lesions measuring <2 cm in their largest diameter (10 cm3 volume), with prescription doses of at >15 Gy. Systemic HPC disease is managed with various chemotherapeutic, immunotherapeutic, and anti-angiographic agents, with limited success. We present a short discussion on CNS HPCs, focusing our discussion on available evidence regarding the role of microsurgical resection, EBRT, SRS, chemotherapy, and immunotherapy for upfront, part of adoptive hybrid surgery approach or for recurrent HPCs.

Hypervascular Lesions of the Cerebellopontine Angle: The Relevance of Angiography as a Diagnostic and Therapeutic Tool and the Role of Stereotactic Radiosurgery in Management. A Comprehensive Review

BACKGROUND

The cerebellopontine angle (CPA) is a narrowed skull base area containing important cranial nerves and vessels and bordering with eloquent areas of the posterior fossa. Tumors of the CPA are a heterogeneous group and can have extradural, intradural/extra-axial, or intra-axial origins. Their vascular supply changes depending on their anatomic origin. Symptomatic, large CPA tumors require surgical resection in order to prevent irreversible, severe neurological damages. However, its tight and strategical location make surgery in the CPA very challenging and require appropriate pre-surgical planning. Pre-surgical diagnosis is of great importance as it allows us to choose the optimal management for the particular patient. This is of further significance when encountering high-risk lesions such as hypervascular tumors. Neurosurgeons should utilize every available pre-surgical diagnostic modalities as well as neo-adjuvant treatments in order to reduce such risks.

METHODS

We review all reported cases of hypervascular lesions of the CPA and discuss the roles of angiography and stereotactic radiosurgery in their management.

RESULTS

Three lesions of the CPA can be considered as truly hypervascular: hemangioblastomas, hemangiopericytomas and paragangliomas. All lesions share many radiological features. However, each lesion has a different anatomical origin and hence, has a characteristic vascular supply. Pre-surgical angiography can be utilized as a diagnostic tool to narrow down the differential diagnosis of a vascular CPA lesion, based on the predominant supplying vessel. In addition, pre-surgical embolization at time of angiography will narrow the associated surgical risks.

CONCLUSIONS

Angiography is a crucial diagnostic and therapeutic tool, helping both in narrowing the presurgical differential diagnosis and in controlling intraoperative bleeding. Because of the high surgical risks associated with resection of vascular tumors in the CPA, noninvasive treatments, such as stereotactic radiosurgery, also may have a crucial role.

Hemangiopericytoma of the Cerebellopontine Angle: A Wolf in Sheep's Clothing

Primary meningeal hemangiopericytoma (HPC) is a rare, aggressive dura based tumor that remarkably mimics a meningioma clinically and radiologically. Its occurrence within the cerebellopontine angle (CPA) is exceptional, and establishing the exact diagnosis is of the utmost importance since total resection remains the cornerstone of treatment. A 42-year-old man presented with a three-month history of progressively worsening vertigo and difficulty in walking. On admission, his neurological examination revealed a right peripheral facial palsy, right abducens palsy and left hemiparesis, suggesting the diagnosis of Millard-Gubler syndrome. Computed tomography and magnetic resonance imaging demonstrated a homogeneously enhancing dura based lesion of the right CPA causing major brain stem compression. There was no widening of the ipsilateral internal auditory canal. A standard retrosigmoid craniotomy was performed to access the right CPA. Exposure of the lesion revealed a well-encapsulated, gray, fibrous lesion, which appeared to originate from the tentorium. Gross total resection was achieved and confirmed radiologically. The microscopic features and the immunohistochemical profile confirmed the diagnosis of a HPC, and adjuvant radiation therapy was administered. Ten years later, the patient presented with a severe neurological deficit due to a local recurrence, but at that time refused any second intervention. He died three months later. HPC can locate within the CPA and present as a Millard-Gubler syndrome. The diagnosis should be kept in mind in case of a CPA dura based tumor. Radical surgery plus radiation therapy can maximize the recurrence-free survival and close follow-up remains mandatory to spot recurrences early.

Stereotactic radiosurgery for intracranial hemangiopericytomas: a multicenter study

OBJECTIVE Hemangiopericytomas (HPCs) are rare tumors widely recognized for their aggressive clinical behavior, high recurrence rates, and distant and extracranial metastases even after a gross-total resection. The authors report a large multicenter study, through the International Gamma Knife Research Foundation (IGKRF), reviewing management and outcome following stereotactic radiosurgery (SRS) for recurrent or newly discovered HPCs. METHODS Eight centers participating in the IGKRF participated in this study. A total of 90 patients harboring 133 tumors were identified. Patients were included if they had a histologically diagnosed HPC managed with SRS during the period 1988-2014 and had a minimum of 6 months' clinical and radiological follow-up. A de-identified database was created. The patients' median age was 48.5 years (range 13-80 years). Prior treatments included embolization (n = 8), chemotherapy (n = 2), and fractionated radiotherapy (n = 34). The median tumor volume at the time of SRS was 4.9 cm³ (range 0.2-42.4 cm³). WHO Grade II (typical) HPCs formed 78.9% of the cohort (n = 71). The median margin and maximum doses delivered were 15 Gy (range 2.8-24 Gy) and 32 Gy (range 8-51 Gy), respectively. The median clinical and radiographic follow-up periods were 59 months (range 6-190 months) and 59 months (range 6-183 months), respectively. Prognostic variables associated with local tumor control and post-SRS survival were evaluated using Cox univariate and multivariate analysis. Actuarial survival after SRS was analyzed using the Kaplan-Meier method. RESULTS Imaging studies performed at last follow-up demonstrated local tumor control in 55% of tumors and 62.2% of patients. New remote intracranial tumors were found in 27.8% of patients, and 24.4% of patients developed extracranial metastases. Adverse radiation effects were noted in 6.7% of patients. During the study period, 32.2% of the patients (n = 29) died. The actuarial overall survival was 91.5%, 82.1%, 73.9%, 56.7%, and 53.7% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. Local progression-free survival (PFS) was 81.7%, 66.3%, 54.5%, 37.2%, and 25.5% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. In our cohort, 32 patients underwent 48 repeat SRS procedures for 76 lesions. Review of these 76 treated tumors showed that 17 presented as an in-field recurrence and 59 were defined as an out-of-field recurrence. Margin dose greater than 16 Gy (p = 0.037) and tumor grade (p = 0.006) were shown to influence PFS. The development of extracranial metastases was shown to influence overall survival (p = 0.029) in terms of PFS; repeat (multiple) SRS showed additional benefit. CONCLUSIONS SRS provides a reasonable rate of local tumor control and a low risk of adverse effects. It also leads to neurological stability or improvement in the majority of patients. Long-term close clinical and imaging follow-up is necessary due to the high probability of local recurrence and distant metastases. Repeat SRS is often effective for treating new or recurrent HPCs.

[Hemangiopericytoma of the cerebellopontine angle: case report and review of literature]

Les hémangiopéricytomes primitifs du système nerveux central sont rares et représentent moins de 1% des tumeurs intracraniennes. La localisation au niveau de l'angle ponto-cerebelleux est très rare, pouvant simuler un neurinome de l'acoustique ou un méningiome. Le diagnostic de certitude est basé sur l’étude histologique et immunohistochimique. Notre but est d'illustrer avec une revue de la littérature les aspects clinico-radiologiques, anatomopathologiques et la prise en charge thérapeutique de ce type de lésion.

Hemangiopericytoma of the posterior fossa: a case report and review of the literature

Intracranial hemangiopericytoma is unusual, and those occurring in the posterior fossa is extremely rare; we report such a rare case of hemangiopericytoma of the posterior fossa. The radiologic findings and gross characteristics of hemangiopericytomas are sometimes quite similar to those of meningiomas. Although extremely rare, the operator should be aware of the existence of this disorder to dexterously manage the aggressive nature and high vascular tendency of hemangiopericytomas. The radiological features and histological findings in this case are discussed in this study.

MRS study of meningeal hemangiopericytoma and edema: a comparison with meningothelial meningioma

Intracranial hemangiopericytomas (HPCs) are rare tumors and their radiological appearance resembles that of meningiomas, especially meningothelial meningiomas. To increase the knowledge on the biochemical composition of this type of tumor for better diagnosis and prognosis, we performed a molecular study using ex vivo high resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) perfomed on HPC and peritumoral edematous tissues. Moreover, to help in the discrimination between HPC and meningothelial meningioma we compared the ex vivo HR-MAS spectra of samples from one patient with HPC and 5 patients affected by meningothelial meningioma. Magnetic resonance imaging (MRI), in vivo localized single voxel 1H-MRS was also performed on the same patients prior to surgery and the in vivo and ex vivo MRS spectra were compared. We observed the presence of OH-butyrate, together with glucose in HPC and a low amount of N-acetylaspartate in the edema, that may reflect neuronal alteration responsible for associated epilepsy. Many differences between HPC and meningothelial meningioma were identified. The relative ratios of myo-inositol, glucose and gluthatione with respect to glutamate are higher in HPC compared to meningioma; whereas the relative ratios of creatine, glutamine, alanine, glycine and choline-containing compounds with respect to glutamate are lower in HPC compared to meningioma. These data will be useful to improve the interpretation of in vivo MRS spectra resulting in a more accurate diagnosis of these rare tumors.

Cellular solitary fibrous tumor (hemangiopericytoma) with anaplasia at cerebellopontine angle--a case report

Cellular solitary fibrous tumor is currently considered a synonym for hemangiopericytoma, as it became increasingly clear that the morphological and immunohistochemical features that separate these two entities have become tenuous, and evidence for a unifying concept has emerged. Furthermore, as no evidence of pericytic differentiation is given in most cases of hemangiopericytoma, this diagnostic term is waning in popularity. We present here a case of cellular solitary fibrous tumor in a 22-year-old man. Neuroimaging revealed a right cerebellopontine angle tumor. Most of the tumor was cellular although some less cellular areas were seen. Sinusoidally dilated large vessels, including staghorn type, were seen. Nuclear pleomorphism and increased mitotic activity (5 mitosis/10 high power field) were regarded as evidence of anaplasia. Diffuse CD34 immunoreactivity and focal positivity for Factor XIIIa were seen in the tumor, which was negative for EMA and S100. The tumor also displayed rich reticulin network. Solitary fibrous tumor at cerebellopontine angle is rare, and 20 such cases (five reported as hemangiopericytoma) have been reported in the English literature.

Concurrent Cochlear Implantation with Resection of Skull Base Hemangiopericytoma following Sudden Deafness in an Only Hearing Ear

A 72-year-old man with a known left acoustic neuroma, left-sided deafness, and a recently diagnosed right infratemporal fossa (ITF) hemangiopericytoma, presented with sudden deafness in his right ear. Imaging revealed right-sided skull base extension and a large intracranial tumor component. The patient underwent a frontotemporal crainiotomy with concomitant ITF approach. Complete tumor resection was possible, though invasion of the otic capsule was present. Immediately postresection, a cochlear implant (CI) was performed via a transmastoid approach. Full electrode insertion was achieved and confirmed by visualization through the dehiscent middle fossa floor. Mastoid obliteration was then performed with a free fat graft. Postoperative imaging confirmed complete tumor resection (Simpson grade I) and adequate CI placement. Follow-up magnetic resonance imaging was performed at 6 and 12 months, and no tumor recurrence was seen. Prior to CI activation, the patient was completely deaf bilaterally. At 18-month follow-up, however, excellent hearing was achieved with the right CI (16 of 22 electrodes active), and the patient is now conversational with no obvious deficit. His cognitive function is excellent, corresponding to preoperative status, and he is independent in his activities of daily living. Following adjuvant radiation, our patient remains disease free at 18 months.

CyberKnife stereotactic radiosurgery for recurrent, metastatic, and residual hemangiopericytomas

Objective

Hemangiopericytoma is a rare and aggressive meningeal tumor. Although surgical resection is the standard treatment, hemangiopericytomas often recur with high incidences of metastasis. The purpose of this study was to evaluate the role of CyberKnife stereotactic radiosurgery (CK) in the management of recurrent, metastatic, and residual hemangiopericytomas.

Methods

In a review of the Stanford radiosurgery database between 2002 and 2009, the authors found 14 patients who underwent CK therapy for recurrent, metastatic, and residual hemangiopericytomas. A total of 24 tumors were treated and the median patient age was 52 years (range 29-70 years) at the time of initial CK therapy. The median follow-up period was 37 months (10-73 months) and all patients had been previously treated with surgical resection. Mean tumor volume was 9.16 cm³ and the mean marginal and maximum radiosurgical doses to the tumors were 21.2 Gy and 26.8 Gy, respectively.

Results

Of the 24 tumors treated, 22 have clinical follow-up data at this time. Of those 22 tumors, 12 decreased in size (54.5%), 6 remained unchanged (27.3%), and 4 showed recurrence (18.2%) after CK therapy. Progression-free survival rate was 95%, 71.5%, and 71.5% at 1, 3, and 5 years after multiple CK treatments. The 5-year survival rate after CK was 81%.

Conclusions

CK is an effective and safe management option for hemangiopericytomas. The current series demonstrates a tumor control of 81.8%. Other institutions have demonstrated similar outcomes with stereotactic radiosurgery, with tumor control ranging from 46.4% to 100%.

Hemangiopericytomas of the skull base

Object

Intracranial hemangiopericytomas are frequently located along the dural sinuses along the skull base and represent rare, aggressive CNS neoplasms that are difficult to distinguish from meningiomas based on both imaging and gross characteristics. The authors of this study describe 3 patients with these lesions and review the pertinent literature.

Methods

Two men and 1 woman, whose median age at the time of the initial presentation was 37 years (range 20–53 years), constitute this series. They underwent multimodal treatment consisting of resection, embolization, radiation therapy, and in 1 case chemotherapy.

Results

Two of the 3 patients treated were alive after a mean follow-up of 93 months (range 4–217 months). One patient died 217 months after the initial diagnosis. The longest tumor progression–free interval after the initial or secondary resection was 43 months (range 4–84 months).

Conclusions

Hemangiopericytomas have been reclassified as mesenchymal nonmeningothelial tumors. They have an inevitable tendency to recur locally and metastasize distally. The mainstay of therapy remains an aggressive attempt to achieve gross-total resection at the initial surgery. Postoperative adjuvant radiotherapy should be offered to all patients, regardless of the degree of resection achieved. Diligent long-term follow-up is paramount as local recurrences and distal metastases can develop sometimes years after the initial treatment.

Predictors of mortality following treatment of intracranial hemangiopericytoma

OBJECT

Intracranial hemangiopericytoma (HPC) is a rare and malignant extraaxial tumor with a high proclivity toward recurrence and metastasis. Given this lesion's rarity, little information exists on prognostic factors influencing mortality rates following treatment with surgery or radiation or both. A systematic review of the published literature was performed to ascertain predictors of death following treatment for intracranial HPC.

METHODS

The authors identified 563 patients with intracranial HPC in the published literature, 277 of whom had information on the duration of follow-up. Statistical analysis of survival was performed using Kaplan-Meier and Cox regression analysis.

RESULTS

Hemangiopericytoma was diagnosed in 246 males and 204 females, ranging in age from 1 month to 80 years. Among patients treated for HPC, overall median survival was 13 years, with 1-, 5-, 10-, and 20-year survival rates of 95%, 82%, 60%, and 23%, respectively. Gross-total resection alone (105 patients) was associated with superior survival rates overall, with a median survival of 13 years, whereas subtotal resection alone (23 patients) resulted in a median survival of 9.75 years. Subtotal resection plus adjuvant radiotherapy led to a median survival of 6 years. Gross-total resection was associated with a superior survival benefit to patients regardless of the addition or absence of radiation, and patients receiving > 50 Gy of radiation had worse survival outcomes (median survival 4 vs 18.6 years, p < 0.01, log-rank test). Patients with tumors of the posterior fossa had a median survival of 10.75 versus 15.6 years for those with non-posterior fossa tumors (p < 0.05, log-rank test).

CONCLUSIONS

Treatment with gross-total resection provides the greatest survival advantage and should be pursued aggressively as an initial therapy. The addition of postoperative adjuvant radiation does not seem to confer a survival benefit.