Chemodectoma of the vagus nerve. Report of a case with ultrastructural study.

Light and electron microscopic studies of a chemodectoma of the vagus nerve are presented. Forty-four cases of vagal chemodectoma have been reported to date, but no electronmicroscopic studies have been published. The ultramicroscopic studies showed the presence of clear and dark cells and membrane-bound neurosecretory granules, and the absence of sustentacular cells and nerve endings. Similar findings have been reported in cases of carotid body and glomus jugulare tumors.