Interleukin-6-producing pheochromocytoma.

A 42-year-old female with high fever and headache was admitted. Physical examination revealed hypertension, thrombocytosis with megakaryocytosis, hyperfibrinogenemia, and high level of serum noradrenaline. After operation of extramedullary pheochromocytoma, all symptoms disappeared and findings became normal. The supernatant of tumor culture showed high levels of interleukin-6.