A hemangiopericytoma is a type of

soft-tissue sarcoma A soft-tissue sarcoma (STS) is a malignant tumour, a type of cancer, that develops in soft tissue. A soft tissue sarcoma is often a painless mass that grows slowly over months or years. They may be superficial or deep-seated. Any such unexplaine ...

that originates in the

pericyte Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body. Pericytes are embedded in the basement membrane of blood ca ...

s in the walls of

capillaries A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...

. When inside the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

, although not strictly a

meningioma Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing ...

tumor, it is a

meningeal In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in t ...

tumor with a special aggressive behavior. It was first characterized in 1942.

Signs and symptoms

Symptoms of hemangiopericytoma vary greatly depending on both tumor stage and affected organs. Most patients report pain and mass-related symptoms, while others also report vascular disease-related symptoms, and some have no symptoms until late in the disease process. Hemangiopericytomas are most commonly found in the meninges, lower extremities,

retroperitoneum The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on their ...

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

lungs The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either si ...

, and

pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips b ...

Histopathology

Hemangiopericytomas are tumors that are derived from specialized spindle shaped cells called pericytes, which line capillaries. Hemangiopericytoma located in the cerebral cavity is an aggressive tumor of the

mesenchyme Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every ...

with oval nuclei with scant cytoplasm. "There is dense intercellular reticulin staining. Tumor cells can be fibroblastic, myxoid, or pericytic. These tumors, in contrast to meningiomas, do not stain with epithelial membrane antigen. They have a grade 2 or 3 biological behavior, and need to be distinguished from benign meningiomas because of their high rate of recurrence (68.2%) and metastases (Maier et al. 1992; Kleihues et al. 1993 )."

Diagnosis

Computerized tomography and magnetic resonance imaging are not effective methods for diagnosis of hemangiocytomas. In practice, a presumptive diagnosis is often reached through exclusion of other soft tissue tumors, and a tissue biopsy is required to confirm diagnosis.

Treatment

Depending on the grade of the sarcoma, it is treated with

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemother ...

, and/or

radiotherapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Rad ...

. Though surgery is the current standard of care for hemangiopericytomas, metastasis and tumor recurrence occur in more than 30% of patients, in particular recurrence in the pelvis and retroperitoneum and metastasis in bone and lungs. Radiotherapy does not appear to provide a significant survival benefit but is recommended for use in patients with tumors greater than 5cm in diameter or with inadequate resection margins after surgery. Clinical benefirs of chemotherapy in soft tissue tumors remains unclear. However, the combination of surgery and chemotherapy appears to worsen survival in hemangiopericytoma patients. More research is needed to determine efficacy of different types of treatment.

Epidemiology

In one series, the median age of affected individuals was 45 years, with a 10-year survival rate of 70 percent. In another study, age over 45 and female sex were associated with worse survival rates in hemangiopericytomas.

References

External links

{{Vascular tumors Dermal and subcutaneous growths Vascular neoplasia Nervous system neoplasia Brain tumor