Hemangiopericytoma: causes, symptoms, diagnosis, treatment

The hemangiopericotoma develops from vessels of the capillary type, is localized more often on the skin of the head and extremities, in the subcutaneous fat layer and skeletal muscles of the lower limbs.

Clinically manifested in the form of tuberous nodular formations, usually solitary, of varying size and density, covered with unchanged or cyanotic-red skin. The tumor grows relatively slowly, can ulcerate, give infiltrating growth and metastasize. It can develop at any age, but more often in individuals over 40 years of age. In children it is more difficult.

Pathomorphology of hemangiopericytoma. The basis of the tumor is newly formed capillaries with slit-like, hardly noticeable lumens. Tumor cells are approximately the same, reminiscent of pericids in appearance, have a weakly eosinophilic cytoplasm containing glycogen and round or oval nuclei filled with euchromatin, with a distinct nuclear envelope. Mitoses are rare. When processing sections with silver salts in the tumor, there are argyrophilic fibers surrounding the lumens of the vessels and separating the endothelial elements from the proliferating pericytes. In some cases, with such treatment, each tumor cell is surrounded by a thin argyrophilic network, which is of diagnostic significance. Proliferation of tumor cells is observed around the vessels, mainly muff-shaped.

In a hemangiopericytome with malignant potency, as in metastases, the cells are usually polymorphic, with the predominance of spindle-shaped forms among them; there is a large number of mitoses. The stroma of the tumor is scarce, the argyrophilic network, although there is, but without a characteristic arrangement, which makes diagnosis difficult.

Histogenesis of hemangiopericytoma. The tumor develops from pericytes, which are located in the walls of capillaries and venules. Electron microscopic examination of hemangiopericytoma shows that in some cases it consists of low-grade cells surrounded not by the basal membrane but by a material that only resembles it. Other authors found typical basal membranes in this tumor. The same author found cytoplasmic filaments and dense corpuscles associated with them in the cytoplasm of tumor elements. Among tumor pericytes, sometimes there are bundles of muscle cells and transitional forms between them.

Differentiate hemangiopereticom primarily from the glomus angioma, which at first glance has a similarity with pericytoma. However, the perithelial elements of the latter are located mainly around the vessels, while the glomus cells are located in the walls of the arterial canals. In addition, the hemangiopericytoma is located in any part of the body, and the glomus-angioma - mainly at the fingertips. From other tumors (hemangiendothelioma, etc.) hemangioperitcioma can be distinguished by the presence of argyrophilic fibers in it.

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