Endocrine Abstracts

Pheochromocytomas are tumors capable of producing catecholamines and a variety of biologically active resulting in unusual clinical manifestations. We report the case of 18-year-old female with pheochromocytoma exhibiting fever of unknown origin. She had experienced continuous fever (ranging between 37.1–41  °C) and chills for previous several weeks. Antipyretics had been ineffective in lowering the body temperature and she was referred to our hospital when an adrenal incidentaloma of 5.5 cm diameter was detected during evaluation for fever. At the time, specific and nonspecific blood and urine cultures yielded in no pathogenic agents with negative viral serological markers. On admission, physical and laboratory examinations revealed normotension, a fever of 38.7  °C, markedly elevated sedimentation rate and CRP level, anemia, thrombocytosis, anemia with high ferritin levels and elevated levels of urinary norepinephrine and normetanephrine. A diagnosis of pheochromocytoma was made and the fever resolved promptly after beginning treatment with adrenergic blockers. Serum interleukin-6 level was measured to be 12.5 (normal; <3.0) pg/ml before adrenergic blockade was started. Additional measurement of 9.9 pg/ml was obtained in the second month of the treatment. She was sent to operation where complete resection of the tumor was achieved. It is suggested that the elevation of interleukin-6 might play an important role in clinical and biochemical inflammatory response. To our knowledge, our paper represents a rare case of interleukin-6 secreting normotensive pheochromocytoma associated with clinical markers of inflammation. Pheochromocytoma should be considered in the differential diagnosis of unexplained fever even for normotensive patients.