Progressive tumor necrosis and lethal hyperkalemia in a neonate with sacrococcygeal teratoma (SCT).

Tumor lysis syndrome is known among patients undergoing induction therapy for lymphocytic malignancies. Spontaneous tumor lysis in patients with solid tumors is distinctly rare. To our knowledge, the phenomenon of spontaneous tumor lysis has been described only once in infancy, in association with the surgical manipulation of a hepatoblastoma. This is the first report of a newborn with sacrococcygeal teratoma who experienced spontaneous tumor lysis-induced hyperkalemia. Because cardiac arrest may be among the leading causes of operative mortality in babies with sacrococcygeal teratoma, intraoperative monitoring of serum K+ should be conducted frequently.