Interleukin-6 Producing Pheochromocytoma: A Rare Cause of Systemic Inflammatory Response Syndrome

Systemic inflammatory response syndrome (SIRS) can be a rare manifestation of pheochromocytoma, since this adrenal tumor may produce cytokines and other hormones or neuropeptides besides catecholamines. We report the case of a 53-year-old female patient with a pheochromocytoma that presented with fever and weight loss of 5% in one month along with normocytic anemia, thrombocytosis, leukocytosis, and elevated C-reactive protein. In this setting, interleukin-6 (IL-6) was requested and was elevated [26.7ng/L (<7.0)]. She also presented biochemical evidence of ACTH-independent cortisol production without overt Cushing syndrome. After adrenalectomy, the inflammatory syndrome resolved and all biochemical parameters normalized, including IL-6 and ACTH. To our knowledge, this is the first case report of IL6-producing pheochromocytoma along with autonomous cortisol production.