An uncommon encounter with tumor lysis syndrome in colorectal cancer.

Tumor lysis syndrome (TLS) is a rare but life-threatening complication in solid tumors such as colorectal cancer (CRC). We report a 61-year-old male with metastatic CRC and extensive liver metastases who developed acute TLS within 48 hours of initiating FOLFOX chemotherapy. He presented with acute kidney injury (AKI), hyperuricemia, hyperphosphatemia, hypocalcemia, and elevated liver enzymes. Prompt treatment with intravenous fluids, rasburicase, and febuxostat led to rapid resolution of TLS. Despite recovery, the patient died two weeks later from complications of advanced metastatic disease. This case highlights the need for early TLS recognition in high-risk CRC patients.