Hemangiopericytoma is a type of soft tissue tumor derived from the capillary walls. Usually this tumor arises in:
- the nervous system, especially in the meninges (dura mater);
- retroperitoneum (24.5%);
- the lower limbs (24.5%);
- head and neck (17%).
It is considered that in 70% of cases hemangiopericytoma is benign.
However, the term “hemangiopericytoma” is no longer conventionally used due to the similarity of these tumors to solitary fibrous tumors. Lately the term has been used only for the meningeal hemangiopericytoma.
Since 1942 when the term was proposed until 1998 only 300 cases of hemangiopericytomas have been reported.
Hemangiopericytoma is extremely rare in adults and comprises about 3% of soft tissue tumors in children. The tumor is more often in females.
Meningeal hemangiopericytomas make less than 1% of all the tumors of the central nervous system.
Hemangiopericytomas originate from the pericytes of Zimmermann. These cells are found in the capillary walls and post-capillary vessels.
The cells of hemangiopericytoma are near-diploid with breakpoints in 12q13, 12q24 and 19q13 with recurrent 1(12;19)(q13;q13) translocations.
In some studies the possible link between the development of hemangiopericytoma and exposure to vinyl chloride or herbicides has been reported.
- Infantile hemangiopericytoma is seen in infants under 1 year;
- Adult hemangiopericytoma;
Meningeal hemangiopericytoma may cause different symptoms, according to the site of the lesion and may include:
- Headache, nausea and vomiting due to increased intracranial pressure;
- Neurologic deficit (muscle weakness, sensory dysfunction);
- Peripheral neuropathy;
As long as the tumor consists of blood vessels, it tends to bleed.
Hemangiopericytomas of other localization occur deep in within the muscles, less common dermal or subcutaneous are detected.
An affected person discovers a painful mass that slowly grows. When the tumor is found in the abdomen the bowel symptoms such as constipation, vomiting, abdominal pain or swelling occur.
Hemangiopericytoma of the pelvis leads to urinary retention, hydroureter, and/or hydronephrosis. Lung hemangiopericytoma causes shortness of breath, discomfort in the chest and cough.
Hypoglycemia as a feature of paraneoplastic syndrome may be seen. It is thought to be the result of the insulin-like growth factor secretion.
The metastases are usually seen in the bones and lungs.
See also: Alveolar rhabdomyosarcoma
- X-ray examination;
It requires the treatment with surgery and radiotherapy. Commonly the wide excision is recommended no matter is the tumor benign or malignant. Before the surgery, arterial embolization may be performed to decrease the bleeding risk.
Adjuvant radiotherapy helps to avoid the recurrence of the tumor. The usual dose is 50 Gy.
Infantile hemangiopericytomaresponses well to chemotherapy. The administration of vincristine, doxorubicin, methotrexate, cyclophosphamide has been investigated.
The survival rate is 86%.