Abstract
A 64-year-old woman with a history of chronic thyroiditis and no family history of endocrine disease was incidentally determined to have a left retroperitoneal mass on abdominal ultrasonography. A subsequent abdominal computed tomography (CT) scan revealed a 5.6 × 5.1 × 10.6 cm left adrenal tumor (10–50 Hounsfield Units of CT attenuation value), which showed marginal irregularity and an internal cystic structure [Figure 1A]. She was admitted to our hospital for further investigation of a suspected adrenocortical carcinoma. On admission, she was normotensive and had no symptoms of catecholamine excess. The 24-hour urine catecholamine level showed normal norepinephrine (122.9 ug/day), epinephrine (24.3 ug/day), whereas markedly elevated dopamine (148,212.4 ug/day). 123I-MIBG scintigraphy revealed tumor uptake. After alpha-blockade as preoperative management, she successfully underwent laparoscopic left adrenalectomy and was finally diagnosed with an exclusively dopamine-secreting pheochromocytoma. The tumor was histologically comprised of small polygonal cells with high cellularity and was immunohistochemically positive for all three catecholamine synthesizing enzymes: tyrosine hydroxylase (very weak), dopamine beta-hydroxylase (heterogeneous), and phenylethanolamine N-methyltransferase (very weak). Electron microscopy revealed very few catecholamine-containing small vesicles with a few organelles, which reflected immature cells. No biochemical or imaging evidence of recurrence or metastasis was evident 1 year after the surgery. To our knowledge, this is the first case of an exclusively dopamine-secreting pheochromocytoma in which immunostaining of catecholamine synthetic enzymes and electron microscopy of tumor tissues were performed together to identify the mechanism underlying a dopamine-secreting PPGL. The purpose of this report was to identify the mechanism underlying a dopamine-secreting pheochromocytoma from the histopathological findings. We also discuss the reasons for the lack of catecholamine excess symptoms, whether preoperative management of alpha-blockade is needed, and the association between the prognosis and genetic mutation with an extensive literature review. JOURNAL/jhype/04.03/00004872-202301001-00862/figure1/v/2023-10-24T163949Z/r/image-jpeg
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
