Radiation Oncology: A Question-Based Review


Steven H. Lin and Ramesh Rengan

image Background

Are hemangiopericytomas benign or malignant lesions?

Hemangiopericytomas are malignant lesions −(sarcomatous lesions of vessels).

What is the cell of origin of hemangiopericytomas?

Hemangiopericytomas were originally thought to −originate from pericytes of the smooth muscle cells of vessels but are now felt to be of fibroblastic origin.

From which other tumor is a hemangiopericytoma of the meninges difficult to distinguish?

Solitary fibrous tumor. The consensus view is that solitary fibrous tumors and hemangiopericytomas belong to the same spectrum of tumors of fibroblastic origin.

What is the most common location of hemangiopericytoma?

The most common location for hemangiopericytomas is in the lower extremity (femur and proximal tibia). Other sites are the H&N, retroperitoneum, and brain (least common). If in the brain, it is a meningeal location, particularly the base of the skull.

What are the incidence and sites of DM in pts with hemangiopericytoma?

~25% (10%–60%) of hemangiopericytoma pts develop hematogenous DMs, with the majority traveling to the lungs > bone > liver (rarely the nodes).

What is the prognosis of hemangiopericytoma as it relates to the location of the tumor?

The prognosis of hemangiopericytoma varies based upon the ability to achieve complete surgical excision.

image Workup/Staging

What are the typical presenting Sx of a pt with hemangiopericytoma?

Pts with hemangiopericytomas present with a firm, painless, localized mass, typically in the extremities.

How do hemangiopericytomas appear on imaging (CT, MRI)?

Hemangiopericytomas typically appear to be hypervascular lesions with diffuse contrast enhancement on CT or MRI.

image Treatment/Prognosis

What is the Tx paradigm for managing hemangiopericytoma?

Hemangiopericytoma Tx paradigm: Complete −surgical resection is the mainstay of therapy + adj or neoadj RT, chemo, or CRT. Unresectable cases can be treated with either radiotherapy alone or chemoradiotherapy with a less favorable outcome.

Is there a role for chemo in the management of hemangiopericytoma?

Yes. Chemo may be used either preoperatively or adjuvantly. Antiangiogenic therapy is currently being explored, as these are highly vascularized tumors.

What is the typical PORT dose used for treating hemangiopericytoma after surgery?

The typical PORT dose is 50–60 Gy to the surgical bed with the margin varying by site.

What is the 5-yr OS for hemangiopericytoma of the meninges?

5-yr OS is ~70% with complete surgical resection. (Guthrie BL et al., Neurosurgery 1989)