Intracranial hemangiopericytomas. Angiography, pathology and differential diagnosis

Sixteen-Year Follow-Up in a Cavernous Sinus Hemangiopericytoma: Improved Outcomes over Radiotherapy Advances

Intracranial hemangiopericytomas are rare tumors, accounting for 1% of all central nervous system malignancies. This tumor is considered at high risk of local and also distant metastases. Surgical excision is the gold standard for treatment, but it is seldom curative by itself. Adjuvant radiotherapy is often recommended. We report an overview and update of the available literature on one such rare but aggressive mesenchymal tumor, using the case of a 46-year-old woman affected by hemangiopericytoma of the cavernous sinus surgically removed and treated with adjuvant radiotherapy at our institution. After seven years, the patient underwent a local recurrence and was treated with exeresis and Gamma Knife radiotherapy. Sixteen years after the initial diagnosis, she is still well with stable disease.

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.

Solitary Fibrous Tumor/Hemangiopericytoma Dichotomy Revisited: A Restless Family of Neoplasms in the CNS

Solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) both entered the literature as separate entities in the early to mid 1900s. In contrast to their central nervous system (CNS) counterparts, there has been a tendency to consider these 2 entities as 1 since the early 1990s, as soft tissue SFT gradually included the tumors previously diagnosed as HPC. The most recent World Health Organization (WHO) classification of the tumors of soft tissue considered the term HPC obsolete, and places all such tumors within the extrapleural SFT category. In contrast, CNS SFT and HPC continue to be regarded as different entities in the latest version of the WHO CNS tumor classification. A change in this approach is currently being considered for the upcoming revision of the WHO scheme, but it is not quite clear whether such a change will be as drastic as the one adopted by the soft tissue and bone tumor working group. This article focuses on the historical evolution of these 2 labels as primary CNS neoplasms, and reviews their differences and similarities in terms of clinical, pathologic, and molecular features.

Angiographic Evidence of a Purely Pial Bihemispheric Intracranial Hemangiopericytoma

Background. Classification of hemangiopericytoma (HPC) has evolved to a mesenchymal, nonmeningothelial grade two or three neoplasm according to the World Health Organization; however its blood supply has always been defined by dual origin, pial and dural contribution. Case Description. We present the case of a patient with an intracranial HPC with only pial vascular supply. Angiography confirmed the lack of dural supply to this bihemispheric intracranial mass. Subsequent histologic examination confirmed the diagnosis of hemangiopericytoma. Angiographic evidence here is atypical of the natural history of hemangiopericytomas with dual vascular supply and was critical in the decision-making towards surgical resection without tumor embolization. Conclusion. Data presented suggests the lack of dural vascular supply alone does not rule out the diagnosis of hemangiopericytoma.

Endovascular embolization of head and neck tumors

Endovascular tumor embolization as adjunctive therapy for head and neck cancers is evolving and has become an important part of the tools available for their treatment. Careful study of tumor vascular anatomy and adhering to general principles of intra-arterial therapy can prove this approach to be effective and safe. Various embolic materials are available and can be suited for a given tumor and its vascular supply. This article aims to summarize current methods and agents used in endovascular head and neck tumor embolization and discuss important angiographic and treatment characteristics of selected common head and neck tumors.

Intradural hemangiopericytoma of the thoracic spine: a case report

BACKGROUND CONTEXT

Hemangiopericytoma (HPC) occurs infrequently in the central nervous system. Spinal involvement is particularly uncommon; and intradural localization is rare. Here, we describe an intradural extramedullary thoracic HPC that went undiagnosed initially on computed tomography scan of the abdomen.

PURPOSE

To describe the clinical presentation and operative management of a patient diagnosed with an intradural extramedullary thoracic HPC that was missed on initial workup. We also describe the pathologic features of HPC.

STUDY DESIGN

Case report.

METHODS

Chart review and literature search.

CASE

A 58-year-old man presented with acute weakness of the lower extremities and bladder and bowel incontinence. Magnetic resonance imaging of his spine revealed a T10 intradural extramedullary lesion that displaced the cord to the right.

RESULTS

The patient was taken emergently to surgery for T9-T11 laminectomy and en bloc resection of the tumor. The lesion was identified and resected. Histology revealed randomly oriented tumor cells with irregular capillaries consistent with HPC. Postoperatively, the patient had an improved neurological examination, and he continued to do so with intense physical therapy.

CONCLUSION

The standard treatment for HPC is surgery when the lesion is resectable. Despite gross total resection, there is still a high risk of recurrence and metastasis; therefore, patients should be followed up closely by their physicians with serial postoperative clinical examinations and radiographic imaging.

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.

Intracranial solitary fibrous tumors: imaging findings in 6 consecutive patients

BACKGROUND AND PURPOSE

Intracranial solitary fibrous tumors (ISFTs) are rare mesenchymal neoplasms originating in the meninges. The aim of this study was to describe the CT, MR imaging, and angiographic features of the solitary fibrous tumor and to identify imaging characteristics.

MATERIALS AND METHODS

We retrospectively reviewed CT, MR, and angiographic findings in 6 cases of ISFT. We evaluated the size, shape, and location of the tumor; the internal content and margin of the lesion; the pattern of enhancement; and the change of the adjacent structures. Density on noncontrast CT scans, signal intensity on MR images, and angiographic features were also documented.

RESULTS

Each lesion appeared as a discrete extra-axial mass (size, 3-7 cm; mean, 5 cm). Five lesions were entirely solid, and 1 had peritumoral cyst. All 5 of the noncontrast CT scans showed hyperattenuated masses, and the tumors exhibited marked heterogeneous enhancement. No lesion contained calcification, and 2 cases showed bone invasions. On the MR images, 4 lesions showed mixed signal intensity on T2-weighted imaging. All of the lesions revealed marked heterogeneous enhancement. All of the tumors had thickening of the meninges adjacent to the tumor. Angiography showed delayed tumor blushing in all, and 3 of them had dysplastic dilation of the tumor vessels.

CONCLUSION

Although there are no pathognomonic imaging findings, some imaging features, such as the "black-and-white mixed" pattern on T2-weighted images and marked heterogeneous enhancement, might be helpful in the diagnosis of intracranial solitary fibrous tumor.

Imaging features of central nervous system haemangiopericytomas

Intracranial and spinal haemangiopericytomas are uncommon, durally based tumours. They macroscopically resemble meningiomas but are distinct histologically, have a more aggressive natural history and require different management. We present a pictorial review illustrating the radiological manifestations of these tumours that will aid in their preoperative identification.

Management of intracranial meningeal hemangiopericytomas: outcome and experience

Hemangiopericytomas represent rare intracranial tumors that have a tendency to recur locally and have the unique characteristic of giving extracranial metastases. Our current communication reviews a series of patients diagnosed with hemangiopericytoma who were treated in our facility. Eleven patients with a mean age of 51.2 years underwent follow-up for a mean time of 7.1 years. Their neuroimaging preoperative evaluation included plain skull X-rays, head CT scans, brain MRI, angiograms, and (1)HMRS. Preoperative embolization of the tumor was employed in 6/11 patients. All patients underwent craniotomy for tumor resection and postoperative radiation treatment was employed on all but one. Grade I resection was accomplished in 6/11 (54.5%), grade III in 4/11 (36.4%), and grade IV in 1/11 (9.1%). Local recurrence was detected in 3/11 (27.3%) at a mean period of 5 (range 2-7.5) years. Extracranial metastatic disease was documented in 4/11 (36.4%) patients at a mean of 4.9 (range 2.5-7) years after the initial diagnosis. The GOS score was: 7/11 (63.6%) scored 5, while 4/11 (36.4%) died at a mean time of 5.5 (range 3-8) years after the initial diagnosis. Intracranial hemangiopericytomas management requires aggressive surgical resection, postoperative radiation treatment, and extensive follow-up to rule out local recurrences and delayed extracranial metastases.

Metastatic liver cancer: A rare case

Hemangiopericytoma is a rare tumor especially when it rises in the peritoneal cavity. We present a case of a 60-year-old woman with an isolated recurrent hemangiopericytoma of the liver. The patient presented with a palpable right upper quadrant abdominal mass, which occurred 7 years after undergoing resection of a malignant hemangiop-ericytoma arising from the greater omentum. She had not followed up 6 mo after surgery. Various imaging studies showed a single large, well-capsulated liver tumor with central necrosis, accompanied by hypervascularity typical of a vascular tumor. Preoperative laboratory HBsAg and anti-HCV workup were both negative. Under the impression of recurrent malignant hemangiopericytoma, right triseg-mentectomy was performed to completely resect the tumor. Pathological examination confirmed the diagnosis of recurrent hemangiopericytoma. Even though the incidence of the hemangiopericytoma is relatively low, malignant hemangiopericytoma has a tendency to recur frequently after a long-term disease-free interval. Also, the recurrent hemangiopericytoma is not easily detected early during follow-up until it becomes symptomatic because there are no specific tumor markers, and because of the diversity with regard to site of recurrence. The authors suggest that Positron Emission Tomogram (PET) may be a useful tool for the detection of recurrent hemangiopericytoma. We describe herein some characteristics and behaviors of malignant hemangiopericytoma, particularly after surgical resection.

Imaging intracranial haemangiopericytomas: study of seven cases

Imaging features of intracranial haemangiopericytomas are similar to those of meningiomas. Preoperative identification of these tumours is important because of their aggressive nature, high rate of local recurrence and propensity for late metastasis. We reviewed the CT, MRI and angiographic findings in seven pathologically proved haemangiopericytomas, to determine if imaging characteristics might distinguish them from meningiomas. None showed hyperostosis or tumour calcification. All showed marked enhancement. Five had prominent internal signal voids, suggesting feeding arteries. On angiography, one had only pial-cortical supply but six also had meningeal supply; all showed a persistent stain. Only one had multiple "corkscrew" feeding vessels.

Hemangiopericytoma of the confluence of sinuses and the transverse sinuses. Case report

The authors describe the case of a 38-year-old man with progressive headache and blurred vision related to a hemangiopericytoma located exclusively in the confluence of sinuses (CoS) and in the transverse sinuses bilaterally. They believe this is the first report in which a hemangiopericytoma of the dural sinuses has been described without any intradural component. Although the diagnosis was not suspected preoperatively, a gross-total resection of the tumor with restoration of sinus patency was achieved to relieve the symptoms. This diagnosis should be included in the preoperative differential diagnosis of a tumor of the CoS. Successful resection can be achieved in these cases.

Hemangiopericytoma in the Trigone of the Lateral Ventricle-Case Report-

A 40-year-old male presented with hemangiopericytoma in the lateral ventricle manifesting as headaches persisting for 6 months associated with vomiting and visual obscurations for one month. Computed tomography and magnetic resonance imaging of the brain showed a large tumor in the trigone of the right lateral ventricle. The highly vascular tumor was completely excised. The histological diagnosis was hemangiopericytoma. Hemangiopericytoma is rarely located in the lateral ventricle and is difficult to differentiate from meningioma by neuroimaging methods.

Solitary fibrous tumor arising from the falx cerebri--case report

A 50-year-old female was admitted with headache and visual disturbance. Neuroimaging demonstrated a well-demarcated large tumor attached to the falx cerebri. The tumor was totally removed by surgery. Histological examination showed that the tumor consisted of spindle cells with no pattern in the collagenous background. Staghorn-like blood vessels were common. Immunohistochemical study showed the tumor cells were strongly positive for CD34 and vimentin, but negative for epithelial membrane antigen. The diagnosis was solitary fibrous tumor arising from the falx cerebri. Solitary fibrous tumor is rare within the cranial cavity, and can be distinguished from meningioma and hemangiopericytoma by the histological, ultrastructural, and immunohistochemical findings.

Hemangiopericytoma of the third ventricle. Case report

The authors present the first reported case of a hemangiopericytoma (HPC) occurring in the third ventricle. Most of these lesions are based in the meninges. There is only one other reported case of an intraventricular HPC; in that case the lesion was found in the lateral ventricle. A 40-year-old right-handed man presented with a 3-month history of headaches. Clinical evaluation, including computerized tomography and magnetic resonance imaging studies, revealed a 1-cm enhancing lesion in the third ventricle. Given the findings on the preoperative imaging studies, the lesion was not consistent with some of the more commonly occurring tumors of the third ventricle, namely colloid cysts. A transcortical approach and resection of the lesion was performed without complication. The final pathological findings were consistent with those of an HPC. Hemangiopericytomas rarely occur in the ventricles and may pose a difficult diagnostic dilemma based on their radiographic and gross appearances, as shown in this case. Because of this difficulty, histological confirmation is required to make a definitive diagnosis. These lesions have a propensity to recur and metastasize in the central nervous system and periphery, thus making the goal of treatment a complete surgical resection followed by postoperative radiation therapy in most cases.

Neuroradiological features of intracranial and intraorbital meningeal haemangiopericytomas

The neuroradiological features of six intracranial and one intraorbital haemangiopericytomas (HP) are reviewed. CT was performed before and after IV contrast medium in 5 patients. In 2 patients MRI was performed before and after contrast medium; in another, only unenhanced images were obtained. Five patients were studied by selective external and internal carotid artery angiography. Women constituted 5 of the 7 patients, and the mean age was 50.5 years, thus the sex and age distribution did not differ from that of typical meningiomas. Contrary to previous reports, calcification was present in two of the intracranial HP, and bone erosion was clearly seen in one intracranial HP and the orbital lesion. On MRI the tumours showed no differences from angioblastic meningiomas. All 6 intracranial HP were aggressive: all recurred following treatment and extracerebral metastasis occurred in one case.

Hemangiopericytoma of the central nervous system: a review of 94 cases

Ninety-four cases of central nervous system hemangiopericytoma (CNS-HPC) are reported. Hemangiopericytoma was found more commonly in men than in women. The mean age at diagnosis was 40.9 years for men and 47 years for women. The tumor was found throughout the entire CNS, usually superficially and closely related to the meninges. Based on multiple histologic variables, the original tumors were divided into differentiated (n = 67) and anaplastic (n = 27). Anaplastic HPC was characterized by the presence of necrosis and/or greater than five mitoses per ten 400x microscopic fields, and at least two of the following microscopic features: hemorrhage, moderate to high nuclear atypia, and moderate to high cellularity. For those patients known to be dead, median survival time was 144 months for differentiated HPC and 62 months for anaplastic HPC. Fifty-seven (60.6%) patients had one or more recurrences and metastasis developed in 22 (23.4%). Thirty-five of 56 patients with differentiated HPC had recurrence, while 22 of 26 patients with anaplastic HPC had recurrence. Bone, liver, lung, central nervous system, and abdominal cavity were the most common sites of metastasis. Postoperative radiotherapy and/or chemotherapy were significantly associated with increased patient survival time.

Intraspinal hemangiopericytoma: case report and review of the literature

Hemangiopericytoma, a tumor whose origin is controversial, rarely affects the central nervous system and is even more rarely spinal. We report a case of the spinal variety and discuss its clinical and pathological features, diagnosis, and treatment in the light of relevant literature.

High activity iodine 125 endocurietherapy for recurrent skull base tumors

Experience with endocurietherapy of skull base tumors is reviewed. We present our cases of recurrent pituitary hemangiopericytoma, radiation-induced recurrent meningioma, recurrent clival chordoma, recurrent nasopharyngeal cancer involving the cavernous sinus, and recurrent parotid carcinoma of the skull base which were all successfully retreated with high-activity 125iodine (I-125) permanent implantation.