Abstract
Episodic hyperkalemia has not been described during resection of a primary thymoma tumor. We present a case of significant intraoperative hyperkalemia during a technically challenging resection of a type B-1 thymoma. The hyperkalemia, presumed to be secondary to considerable tumor manipulation, was successfully controlled with calcium, bicarbonate, and insulin with dextrose. Although strict criteria for tumor lysis syndrome were not met, this possibility was included in the differential diagnosis. This case highlights the importance of close intraoperative electrolyte monitoring and prompt treatment of hyperkalemia during challenging thymoma resection.