Hyper-dopaminemia may produce an increased outlet resistance of the prostatic urethra: a case report of malignant pheochromocytoma.

We report on a 43-year-old man with difficult urination attributed to malignant pheochromocytoma with hyper-dopaminemia. A decrease and increase in the plasma dopamine values during the clinical course clearly coincided with improvement and deterioration, respectively, in urination difficulty. The prostatic peak pressure decreased by 37% when the plasma dopamine value was minimal. Detrusor function was normal throughout. Endocrinological and urodynamic studies suggested that hyper-dopaminemia produced an increased outlet resistance of the prostatic urethra without altering detrusor function. Thus, peripheral dopaminergic systems may influence voiding mechanisms, especially those involving the proximal urethra.