Histomorphometric and morphologic studies of the carotid body and aortic paragangliomas.

: Morphometric and morphological parameters have been evaluated in tumours of carotid body paraganglia and of aorticopulmonary and aorticosympathetic paraganglia. Paragangliomas are characterized by a higher cell density and rounder nuclei (roundness factor) than non-neoplastic carotid body paraganglia. The nuclear area has similar mean values in tumours and normal paraganglia; however, the former group shows higher standard deviation values and coefficients of variation, reflecting the fact that paragangliomas have nuclei of variable size; the variation is more pronounced in aorticopulmonary and aortico-sympathetic paragangliomas. However, subgroups on the basis of morphological features (architectural patterns and degree of intensity of argyrophilia), site of origin, and clinical behaviour (metastases and recurrences) show no morphometric differences.