How does dopamine play into the laboratory diagnosis of pheochormocytoma?

Several studies have indicated associations of malignant chromaffin cell tumors with increased urinary output or plasma concentration of dopamine. In part, this finding appears to reflect associations of malignancy with SDHB mutations and extra-adrenal tumors, often character ized by dopamine production.

Eisenhofer, Graeme. “Screening for pheochromocytomas and paragangliomas.” Current Hypertension Reports 14.2 (2012):130-7.

Pheochromocytomas and paragangliomas are highly heterogeneous neuroendocrine tumors that must be considered not only in patients with hypertension and other manifestations of catecholamine excess but also in patients with incidentalomas or mutations in one of the ten tumor susceptibility genes identified to date. To first think of the tumor remains the critical step for screening in patients with signs and symptoms. In these patients, biochemical testing is straightforward and should include measurements of plasma or urinary metanephrines, comprising separately measured normetanephrine and metanephrine. Tumors due to an underlying germline mutation are often found in the absence of hypertension or other signs or symptoms of the tumor. Screening for disease in these patients can benefit from an individualized approach according to the particular mutation. Additional measurements of methoxytyramine, the metabolite of dopamine, can be useful in patients with mutations of succinate dehydrogenase genes or patients who are at risk for malignancy

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