Esophageal carcinosarcoma presenting as a fever with elevated serum interleukin-6

We report a patient with esophageal carcinosarcoma who initially presented with fever. A 57-year-old man with a 4-month history of intermittent fever was referred to our hospital and diagnosed as having esophageal carcinosarcoma. High fever persisted and serum concentration of interleukin-6 was markedly elevated. In contrast, after thoracic esophagectomy, the fever subsided and interleukin-6 serum levels rapidly normalized. The clinical course of the patient suggests that the tumor produced interleukin-6 and this was associated not only with inflammation, but also the aggressive biologic behavior of the tumor.