[Classification of head and neck paragangliomas]

The terms glomus or chemodectoma arose with knowledge of the histological structure of these tumors; their paraganglionic cells, together with autonomic ganglion cells, form the paraganglia, and consequently the most appropriate term to describe these tumors is paraganglioma. Classification of these tumors varies according to the parameter chosen: patient age, secretory capacity or biochemical behavior, whether the tumor is isolated or syndromic, or benign or malignant, etc. Moreover, there are other classifications based on other features such as localization, extension, the recommended surgical approach, immunohistochemical characteristics of the tumor, whether the tumor is hereditary, etc. None of these criteria have been universally accepted. Thus, in the present article, the most important criteria will be described. By paying attention to their localization, extension and the recommended surgical approaches, the classification of these tumors has progressed and, at the same time, diagnostic imaging tests and surgical techniques have improved. This type of classification is of great interest from the clinical-surgical point of view and consequently the present article describes them in detail, especially in temporal and carotid body paragangliomas.