When the Tumor Lyses: A Case Report on Spontaneous Tumor Lysis Syndrome.

Tumor lysis syndrome (TLS) is an oncological emergency characterized by severe electrolyte disturbance that typically occurs when hematologic cancer patients have been started on systemic chemotherapy. We present an uncommon case of spontaneous TLS (STLS) occurring in a patient with cholangiocarcinoma. The patient was a 59-year-old male with newly diagnosed differentiated carcinoma of unknown origin who presented with weakness, fatigue, and lightheadedness. Initial imaging revealed cholangiocarcinoma with innumerable pulmonary and hepatic metastases. The laboratory values showed leukocytosis, hypercalcemia, and lactic acidosis. He was diagnosed and treated for sepsis of pulmonary origin. Over the next 3 days, the patient's clinical condition steadily worsened despite aggressive treatment, with new-onset hypoxic respiratory failure, acute kidney injury, and septic shock. Chemotherapy was administered, with new laboratory values showing hyperuricemia and hyperkalemia, consistent with STLS. The patient was transferred to the ICU and emergently started on dialysis but expired a day later from multi-organ failure. To our knowledge, this is the second case of STLS in cholangiocarcinoma. Our patient was unique in that he presented with hypercalcemia and normal phosphorus levels, instead of the typical hyperphosphatemia and secondary consumptive hypocalcemia. While the exact pathophysiology of STLS is still elusive, we believe that the patient's initial sepsis-induced hypotension, aggressively enlarging tumor, and extent of metastasis all contributed to his rapid decline. Given the high mortality rate with TLS and its vague presentation, particularly in a chemotherapy-naïve solid tumor, a high level of clinical suspicion is needed to improve patients' outcome.