Primary epidural hemangiopericytoma in the sacrum: a rare case and literature review

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.