Radiation Oncology/Sarcoma/Hemangiopericytoma

Hemangiopericytoma

Overview

• Malignant vascular tumor
  • Tumor cells appear like smooth muscle cells, but don't arise from endothelial cells
  • Cell of origin not clear, possibly derived from pericytes
• Most commonly in pelvic, proximal femur, humerus, and vertebral bodies
• Median age in 4th and 5th decade
• Typically slow growing
• Radiography not definitive
  • Easily confused with meningioma. No calcifications or hyperostosis on CT (where as meningiomas have these features)
  • larger lesions will show flow voids on MRI.
• Treatment frequently surgical, role of chemo and RT not clear, although small series show lower rates of recurrence with addition of radiotherapy.

• Heidelberg, 2005 (Germany) (1984-2004) PMID 16222690 — "Precision radiotherapy for hemangiopericytomas of the central nervous system." (Combs SE et al. Cancer. 2005 Dec 1;104(11):2457-65.)
  • Retrospective. 25 patients. 23 surgical resection. Treated with fractionated stereotactic RT or IMRT for tumors of the CNS and spine. Median dose 54 (in 1.8-2 Gy/fx)
  • OS: 5-years 100%, 10-years 64%. 5-year PFS 61%
  • Conclusion: "High precision" RT effective and safe