A case of spontaneous tumor lysis syndrome in extensive-stage small-cell lung cancer: A rare oncologic emergency.

Tumor lysis syndrome (TLS) is an oncologic emergency. It generally occurs after chemotherapy but sometimes develops spontaneously in hematologic malignancy, such as leukemia. TLS is a rare phenomenon in patients with solid tumors, particularly when it develops spontaneously. Here, we present a case of spontaneous TLS (STLS) in a patient with small-cell lung cancer (SCLC). We report a case of STLS in a 59-year-old male patient who presented with dyspnea and oliguria. Clinicians should suspect TLS in patients with malignancy, who demonstrate the classic electrolyte abnormalities of TLS even if not receiving treatment such as chemotherapy or radiotherapy.