Spontaneous TLS Preceding the Diagnosis of Metastatic Prostate Cancer

Tumor lysis syndrome (TLS) is an oncologic emergency characterized by electrolyte abnormalities that arise with rapid turnover of tumor cells and subsequent release of intracellular contents. Although TLS is commonly associated with hematologic malignancies, there is a growing body of evidence demonstrating the occurrence of TLS in patients with solid tumors. Although TLS is typically associated with the start of chemotherapy, it can rarely occur in its absence, a phenomenon termed “spontaneous TLS” (STLS). While diagnostic criteria for TLS are widely accepted, there are no clearly defined criteria for the diagnosis of STLS. Here, we report a case of STLS secondary to previously unidentified metastatic prostate cancer and discuss the challenges of diagnosing STLS in the setting of acute renal injury.