Hemangiopericytoma

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Hemangiopericytoma
Hemangiopericytoma.jpg
MRI showing posterior fossa hemangiopericytoma
Tumor Class Sarcoma
Cell of origin Pericyte
WHO Grade WHO
Survival Survival 5 yr -67%, 10yr - 40%, 15 yr = 23%
Treatment Surgery and Radiation
Histologic Features
Radiographic Features

Contents

Definition

Intracranially, these are dural based lesions that were historically considered a variant of meningioma. They arise from pericyte cells (Zimmerman pericytes) that are contractile and surround capillaries and post-capillary venules. They are currently considered a type of solitary fibrous tumors and occur in many locations.

Epidemiology

Mean age of onset ranges from 32-41 years with a male predominance (for intracranial tumors). Approximately 10% will occur in children. They account for <1% of all intracranial tumors and <2.5% of all meningeal tumors.

Diagnosis

Hemangioperictyomas will present as an intracranial mass lesion. They are generally supratentorial. They can also present elsewhere in the neural axis including the spine. The most common site of presentation is the lower extremity (especially the thigh). Most tumors are deep seated and are found in muscle tissue. Hypoglycemia may occur, particularly from tumors in the pelvis, as these tumors secrete insulin-like growth factors, and insulin-like growth factor receptors.

Imaging

The imaging study of choice is MRI with a T1 weighted post-contrast image being the most useful imaging modality. These lesions are frequently dural based and will mimic meningioma.

Axial T1 weighted MRI with contrast showing a left cerebello-pontine angle hemangioperictyoma. Note its dural based nature.

Treatment and prognosis

Surgical resection is considered the mainstay of treatment. Due to a high recurrence rate, gross total resection at the initial surgery is the treatment option of choice. Local control rates after gross total and subtotal resections are 84% and 38% respectively. Five year disease-recurrence free rates are 73% and 21% for GTR and STR respectively. Radiotherapy has been shown to significantly increase progression free survival rates. Stereotactic radiosurgery has also been shown to be an effective treatment for recurrent hemangiopericytomas. In general, 5- and 10- year survival rates range from 67-96% and 40-75% respectively. Of note, hemangiopericytomas may metastasize (10-30%), and frequent sites include the lung, liver and bone. There are no established chemotherapy regimens.

Pathology

Hemangiopericytoma has distinct pathologic findings including dense cellularity with mitotic figures, and reticulin. Staghorn vascular channels are a hallmark. There is an absence of psammoma bodies or whorls (seen in meningioma). Immunohistochemistry is positive for vimentin, but not EMA (seen in meningioma).

References

  1. Cancer. 2004 Apr 1;100(7):1491-7
  2. Neurosurgery. 1989; 25: 514-522
  3. Neurosurgery. 2002; 51: 905-911
  4. J Surg Oncol. 2008 Mar 15;97(4):321-9
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