Functional carotid paragangliomas. Biochemical, ultrastructural, and histochemical correlation with clinical symptoms.

To our knowledge, this study is the first to correlate the results of biochemical, electron microscopic (EM), and histochemical analyses of tissues from functional paragangliomas of the upper carotid area with a patient's clinical symptoms. The tumor tissues from our two patients contained epinephrine, norepinephrine, and dopamine. Neurosecretory granules were identified in both tumors by EM and by the Grimelius silver stain. The patient with the most severe symptoms exhibited evidence of higher circulating levels of catecholamines by biochemical, EM, and histochemical analyses.