Interleukin-6-producing paraganglioma as a rare cause of systemic inflammatory response syndrome: a case report

Pheochromocytomas and paragangliomas (PPGLs) may secrete hormones or bioactive neuropeptides such as interleukin-6 (IL-6), which can mask the clinical manifestations of catecholamine hypersecretion. We report the case of a patient with delayed diagnosis of paraganglioma due to the development of IL-6-mediated systemic inflammatory response syndrome (SIRS). A 58-year-old woman presented with dyspnea and flank pain accompanied by SIRS and acute cardiac, kidney, and liver injuries. A left paravertebral mass was incidentally observed on abdominal computed tomography (CT). Biochemical tests revealed increased 24-hour urinary metaneph-rine (2.12 mg/day), plasma norepinephrine (1,588 pg/mL), plasma normetanephrine (2.27 nmol/L), and IL-6 (16.5 pg/mL) levels. 18F-flu-orodeoxyglucose (FDG) positron emission tomography/CT showed increased uptake of FDG in the left paravertebral mass without me-tastases. The patient was finally diagnosed with functional paraganglioma crisis. The precipitating factor was unclear, but phendime-trazine tartrate, a norepinephrine-dopamine release drug that the patient regularly took, might have stimulated the paraganglioma. The patient's body temperature and blood pressure were well controlled after alpha-blocker administration, and the retroperitoneal mass was surgically resected successfully. After surgery, the patient's inflammatory, cardiac, renal, and hepatic biomarkers and cate-cholamine levels improved. In conclusion, our report emphasizes the importance of IL-6-producing PPGLs in the differential diagnosis of SIRS.