Distinctive Characteristic Features of Intramedullary Hemangiopericytomas

Spinal intradural solitary fibrous tumor/ hemangiopericytoma with intramedullary invasion mimicking a hemangioblastoma

Background:

Solitary fibrous tumor/hemangiopericytomas (SFT/HPCs) are rare mesenchymal tumors of nonmeningothelial origin that comprises <1% of all central nervous system tumors.

Case Description:

A 45-year-old male presented with sleep apnea (apnea-hypopnea index was 17.1 events/hour) and dysesthesias of the right upper and lower extremities. The magnetic resonance demonstrated a heterogeneous intradural extra-axial C1 mass with syringobulbia and syringomyelia. The right vertebral angiography revealed a hypervascular mass (i.e., intense tumor staining). With the preoperative diagnosis of a spinal hemangioblastoma, the patient underwent tumor removal. However, intraoperative findings demonstrated that the ventral component of the tumor was intramedullary without a dural attachment. Further, the histological diagnosis was consistent with SFT/HPC (HPC phenotype). The postoperative course was uneventful, and the patient’s symptoms and the syrinxes spontaneously regressed.

Conclusion:

A 45-year-old male presented a rare spinal intradural lesion at C1 appeared to be a spinal hemangioblastoma, but proved to be SFT/HPC (HPC phenotype) with intramedullary invasion.

Intradural Extramedullary Solitary Fibrous Tumor of the Thoracic Spinal Cord

Solitary fibrous tumors (SFTs) are rare soft tissue neoplasms that can impact the central nervous system (CNS). SFTs comprise <1% of all primary CNS tumors. Here, we describe a rare case of intradural, extramedullary SFT arising within the thoracic spine that was treated with surgical resection. Histological features were evaluated and revealed a highly cellular tumor with positive expression of BCL2, CD34, CD99, and STAT6 proteins that are consistent with a diagnosis of SFT. We discuss the use of surgical intervention for long-term disease control of spinal SFT and evaluate the role of postoperative radiation therapy in management strategies. Lastly, we review the literature reports of intradural, extramedullary SFTs in the thoracic spine. The importance of molecular characterization by histopathology to properly determine diagnosis and prognosis is emphasized.

A Rare Case of a Primary Spinal Solitary Fibrous Tumor/Hemangiopericytoma in a 9-Month-Old Patient

BACKGROUND Solitary fibrous tumors (SFTs)/hemangiopericytomas (HPCs) are mesenchymal tumors commonly found in middle-aged patients, usually localized to thoracic pleurae. Spinal tumor involvement is rarely seen, and its imaging findings are largely inconsistent because of the rarity of these cases. We present a case report of a 9-month-old girl with a rare intraspinal tumor with histologic evidence of SFT/HPC, but no STAT6 nuclear immunoreactivity. CASE REPORT A 9-month-old girl, born at term with good prenatal care, presented to the emergency room with regression of developmental milestones. The patient was in good health until 2 months, when she developed decreased spontaneous leg movements. Physical exam revealed diffuse muscular atrophy, with no deep tendon reflexes, sensation, or spontaneous movements of the lower extremities. Computed tomography and magnetic resonance imaging showed a heterogeneous irregular mass filling the lumbosacral spinal canal, extending through the neural foramina to the prevertebral/perivertebral and presacral regions. The tumor was biopsied and referred to the National Institutes of Health for consultation and the diagnosis of SFT/HPC was confirmed on the basis of its histologic features, despite the fact that the tumor was negative for STAT6 immunoreactivity. CONCLUSIONS Although the tumor histology was consistent with SFT/HPC, it was negative for STAT6 nuclear immunoreactivity, which is unusual and may exclude the diagnosis. To our knowledge, this is the youngest patient to present with a spinal SFT with these features.

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.

Primary epidural hemangiopericytoma of the thoracic spine: Case report and literature review

Hemangiopericytoma (HPC) is a rare tumor originating from pericapillary cells. Rarely found in the central nervous system, it is extremely rare in the spinal canal. Because of the low incidence of this tumor, its radiographic features and clinical manifestations have not been extensively studied and reported, therefore, it is often misdiagnosed as a schwannoma or spinal meningioma. We describe an unexpected HPC in a 35-year-old woman who was admitted to the Peking Union Medical College Hospital with a severe backache, sensory abnormalities, and muscle weakness. Magnetic resonance imaging showed an enhancing lesion at T6-7 with severe compression of the spinal cord. Gross total resection was achieved, and subsequently, a marked neurologic improvement was observed. The diagnosis of primary extradural HPC in our patient was confirmed based on postoperative histopathology and immunohistochemistry. Neither recurrence nor metastasis of the tumor was found during the 14-month follow-up, which did not include radiotherapy. To describe the demography, radiologic features, treatment, and prognosis of spinal HPC, a comprehensive literature review was performed and 105 cases of primary spinal HPC from 1958 to 2017 were collected from 39 articles. Although rare, HPC should be considered in the differential diagnosis of intraspinal lesions. Immunohistologic examination is of decisive importance in making the diagnosis. Adequate surgical resection, when feasible, is the first choice of treatment for all cases of HPC; however, the outcomes of radiotherapy and chemotherapy have yet to be determined. Individualized treatment combined with long-term follow-up for each patient is recommended.