*, Mehdi Kashani

Introduction: Tumor lysis syndrome is a critical oncologic emergency most commonly associated with hematologic malignancies. However, it can also occur in patients with solid tumors, especially following systemic cytotoxic chemotherapy. Prompt identification and management are essential, as this syndrome can rapidly lead to severe metabolic disturbances, acute kidney injury, and multiorgan failure. Case Presentation: We describe a 65-year-old woman with a history of metastatic uterine leiomyosarcoma who presented to the emergency department with progressive weakness, lightheadedness, and hypotension, six days after receiving a cycle of doxorubicin and trabectedin with concurrent pelvic radiation. Initial evaluation revealed tachycardia, hypotension, pancytopenia, elevated lactate, rising creatinine, and electrolyte abnormalities including hyperkalemia and hyperuricemia. Imaging identified a necrotic pelvic mass and bilateral hydronephrosis. Tumor lysis syndrome was diagnosed and treated with intravenous fluids, rasburicase, and electrolyte correction. Despite initial efforts, the patient developed worsening kidney function, requiring urgent hemodialysis and admission to the intensive care unit. Her clinical course was further complicated by vasopressor-dependent shock, and ongoing tumor necrosis. Nephrology, oncology, critical care, surgery, and palliative care teams were engaged throughout her hospitalization to provide coordinated management and support. Conclusion: This case illustrates the potential for tumor lysis syndrome to occur in solid tumors following chemotherapy and the vital role of emergency physicians in early recognition and initiation of treatment. Multidisciplinary care and early involvement of palliative services are essential in managing these complex, high-acuity cases and ensuring patient-centered outcomes.