[Case report of catecholamine-secreting carotid body tumor].

We encountered a case of catecholamine-secreting carotid body tumor which has never been reported in Japan. The patient was a 20-year old man, who complained of a mass located at the right neck and hypertensive symptoms such as loss of consciousness at extension of the neck, fatigability, etc. Carotid angiography and computed tomography (CT scan) revealed a carotid body tumor. Before operation, a mild hypertension was noted, serum and urinary levels of norepinephrine showed abnormal increase, and phentolamine test was positive. After the tumor was dissected by a surgical procedure associated with carotid reconstruction, blood pressure and norepinephrine levels clearly trended to decrease and phentolamine test returned to negative. Histopathologically, the tumor was a paraganglioma with so-called "organoid" pattern. The tumor was not chromaffin, but the presence of neurosecretory granules was confirmed under electron microscope. In one-year follow up after the operation, no sign suggestive of "latent" or newly arising paraganglioma was noted in assay of catecholamines in serum and urine, nor on adrenal CT scan.