C51-36 Tumor Lysis Syndrome in Metastatic Uterine Sarcoma: A Rare Oncologic Emergency in Solid Malignancy

Abstract Tumor lysis syndrome is an oncologic emergency that results from the breakdown of malignant cells. The disease is characterized by metabolic derangements such as hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. TLS is most associated with hematologic malignancies with high cell turnover and chemosensitivity such as ALL and Burkitt lymphoma. It can rarely occur in solid tumors with a high tumor burden or metastatic disease. 57-year-old woman with stage IV poorly differentiated uterine sarcoma and recent initiation of her first cycle of carboplatin, paclitaxel, and dostarlimab who presented with weakness and fatigue. Upon initial evaluation she was found to have an AKI with a Cr of 2.2 and multiple electrolyte abnormalities including a uric acid level of 25.7, K 5.4, and Ph 7.2. There was a high clinical suspicion for tumor lysis syndrome despite her tumor not being classically associated with TLS. She was transferred to the ICU and over the course of 3 days received aggressive fluid resuscitation and 3 total doses of rasburicase until normalization of her uric acid level to 7.8. Following resolution of her TLS, her further hospital course was complicated by hemorrhagic shock from her tumors given the extensive vascularity requiring MTP and bilateral pulmonary emboli found on CT scan. Our case highlights the rarity of TLS in the case of solid malignancy with large burden metastasis. In the guidelines by the American Society of Clinical Oncology, it was found that in adult patients with solid tumors, only 1% of those cases were associated with TLS. Despite uterine sarcoma not being a classic TLS-associated tumor, the rapid cytoreduction induced by therapy, combined with the high tumor burden, triggered her presentation. Her treatment regimen included carboplatin and paclitaxel, which cause rapid tumor cytoreduction, and adding dostarlimab, an immune checkpoint inhibitor, may have potentiated tumor lysis by enhancing the immune-mediated destruction of malignant cells. While rare, this report adds to the growing recognition of TLS in non-hematologic cancers and the importance of early diagnosis and proactive management. Prompt management in this case successfully allowed for resolution of TLS despite further complications from her malignancy. This abstract is funded by: None