Dopamine-secreting glomus vagale : A case report and histopathologic correlation

Background. Catecholamine secretion by head and neck paragangliomas is uncommon. Dopamine secretion by these tumors has not routinely been assessed. This case report describes a dopamine-secreting glomus vagale and evaluates seven other paragangliomas immunohistochemically for their ability to synthesize dopamine. Methods. Light microscopic and immunohistochemical studies were performed on eight tumors, and biochemical testing for serum/urine catecholamines was performed on two patients. Results. One patient (case report) had elevated serum dopamine which corrected following surgery. Five tumors stained strongly positive for the presence of tyrosine hydroxylase, the critical enzyme in the biosynthesis of dopamine. Conclusion. This case report describes the ability of a glomus vagale to secrete dopamine. Other paragangliomas express the enzymatic machinery necessary to begin catecholamine synthesis. Now that dopamine is routinely screened during catecholamine determination, other cases may be identified.