Radiologic findings in peripheral neurilemoma.
Neurilemoma is a primary nerve sheath tumour that usually arises from a peripheral nerve. In a series of eight solitary neurilemomas four benign and four malignant tumours are observed. Three neoplasms are of intrathoracic origin, four tumours arise in the retroperitoneal space and one tumour develops in the duodenal wall. Radiographic findings using computed tomography, ultrasonography and arteriography are presented. All neurilemomas show relatively low density in CT compared with other parenchymal tumours. All benign and three of the malignant neurilemomas reveal good contrast enhancement. Arteriography has an important role in defining the tumour's blood supply and establishing the origin of the tumour. Five of six neurilemomas show hypervascularity in arteriography. Ultrasonography shows cystic degeneration in three malignant and in one benign neurilemoma. Pathologic correlation of peripheral neurilemoma is discussed by using a special immunoperoxidase technique.