Vascularization of peripheral neurilemomas: angiographic, computed tomographic, and histologic studies.

The vascularization of peripheral neurilemoma was studied in 17 patients, in eight by angiography and in 16 by computed tomography (CT) using contrast enhancement. Angiographically the degree of vascularity varied from scarcity to abundance of vessels. In two patients, arteries connected to the proximal and distal poles of the tumor could be identified as nutrient arteries of the affected nerve, and in three patients some of the veins draining the tumor followed the course of the nerve. All 16 tumors examined by CT showed lower density than skeletal muscle. They were well delineated and at least partially surrounded by adipose tissue. With contrast enhancement the density increased focally, reflecting the distribution of vessels in the tumors. Histologic examination showed that Antoni-A tissue was rich in small (below 15 micron) and medium-sized vessels, whereas large vessels (above 100 micron) were more frequently seen in Antoni-B tissue. Medium-sized and large vessels often tended to be arranged along the border between Antoni-A and Antoni-B tissues.