Perizoma (from the Greek. peri - around and kytos - cell; synonym: perihelion, endothelioma perivasculare, sarcoma angioplasticum, sarcoma peritheliale) - the tumor consisting of atypical adventitious or peritonealny cells located in the form of clutches around capillaries or precapillaries. Histogenesis perechitay unclear. Some researchers deny the existence of P. as an independent tumors. Others believe that P. develops from endothelial perivascular vessels (endothelioma perivasculare). Many authors identify P. with angiosarcomas, carry it to one of the types angioplasticheskih sarcoma or sarcomatosis angioma. Also suggested that the PA is of sympathetic-neurogenic tumors type paraganglioma.
Macroscopically, perizoma is single or multiple tumor nodes reddish-gray color. Occurs in the skin, soft tissues, in the internal organs. Typical localization is not.
In the early stages of tumor nodes isolated little brazed with surrounding tissues; later, merging, individual nodes form a rough tumor infiltrating the surrounding tissue. The tumor tends to decay, bleeding. The value perechitay can be different - from 0,5 up to 15-20 cm in diameter.
Histologically Ii. has a rather typical structure. Around the capillaries and precapillaries lined normal endothelium, are atypical polymorphic tumor cells - round, spindle-shaped polygon. Nuclei of tumor cells hyperchromic. The cells are arranged concentrically or radially, forming a kind of wide clutch around blood vessels. Tumor tissue is directly connected to the vascular endothelium, which retains its normal pattern. Sometimes connective tissue stroma shares complexes of tumor cells that gives P. alveolar structure. In peacetime may experience hyalinosis vessels, rarely stroma. Often there are foci of necrosis, but especially the periphery of tumor couplings.
In cases where the individual tumor clutch merge, connection of the tumor blood vessels become less visible and P. on histological structure gets similarity sarcoma, often veretenoobraznaya. Sometimes I have problems with the differentiation perechitay and sarcoma UNGA because the Ewing sarcoma (see Bone tumor) tumor cells are also located around the thin-walled vessels lined normal endothelium.
P. is quite rare. Clinically relatively benign, but in some cases has infiltrating, destructive growth, persistently recurs. Sometimes it spreads quickly, usually in the lungs.
Treatment of surgery followed by radiotherapy.