Cairo-Bishop criteria for TLS A rare occurrence of tumor lysis syndrome in non-hematologic solid tumor: Breast Cancer Deepankar Sharma MD, Rahul Gosain MD, Amitoj Gill MBBS, Joshua Rubenfeld MD Johns Hopkins University / Sinai Hospital Program in Internal Medicine, Baltimore, MD INTRODUCTION Tumor lysis syndrome (TLS) is an oncologic emergency that is caused by tumor cell lysis with release of intracellular material such as potassium, phosphate and nucleic acids into the circulation. Further, build up of uric acid secondary to breakdown of nucleic acid in the systemic circulation results in hyperuricemia. TLS is most commonly seen in the setting of a malignancy of high proliferative rate, large tumor burden and/or in a malignancy with high sensitivity to treatment. Most often, TLS occurs after initiation of cytotoxic therapy in high-grade hematologic malignancies, however, it can occur spontaneously and with other non-hematologic malignancies but is usually a rare finding (1). In the year 2004, Cairo-Bishop definition was proposed with specific laboratory criteria for the diagnosis of TLS. Two or more laboratory changes (as outlined in Table 1) within three days before or seven days after cytotoxic therapy qualifies for laboratory TLS (2). Further, clinical TLS is defined as laboratory TLS along with one or more of the following: Cardiac arrhythmias, sudden death, seizure or 1.5 times increase in serum creatinine concentration from the baseline. . CASE PRESENTATION A 28-year-old woman, 28 weeks pregnant with a history of metastatic breast cancer presented with visual disturbances and was noticed to have seizure activity lasting thirty minutes resulting in her intubation for airway protection.   Patient was initially diagnosed with invasive ductal carcinoma of her breast with ER/PR positive and Her-2-neu negative two years ago. At the time of diagnosis, patient was offered radiation and chemotherapy that she declined. On her current admission, patient was noticed to have metastatic disease with numerous hepatic lesions and diffuse involvement of the osseous structures: intracranial, cervical, thoracic and lumbar vertebra involvement. During her hospital course, with rapid decline, patient’s uric acid and phosphate levels were elevated along with hypocalcemia (outlined in Table 2). With given clinical presentation and laboratory results, patient met the clinical and the laboratory “Cairo-Bishop” definition of tumor lysis syndrome. She was started on allopurinol and aggressive fluid therapy. Patient responded well to this intervention and over the course, she had a rapid decline in her uric acid levels and normalization of other electrolyte derangement. DISCUSSION Tumor lysis syndrome is one of the most dreaded complications of aggressive malignancies but is rarely noticed in non-hematologic solid tumors (3). The cornerstone of preventing TLS under all the circumstances is adequate hydration along with urinary alkalinization and hypouricemic agents (1). Despite appropriate preventive measures, a small percentage of patient population develops TLS. Patients who present with or develop TLS should receive intesive care with continuous cardiac monitoring and aggressive monitoring of electrolytes, creatinine and uric acid levels (1). CONCLUSION In literature, 370 cases have been reported of TLS in solid tumors of which only 10 cases in association with breast cancer (4). Presentation of this individual is of value because TLS is a rare occurrence in solid tumors but clinicians should be aware of it to avoid poor clinical course. The potential severity of complications from TLS such as cardiac arrhythmias, renal failures, seizure or death necessitates preventive measures and prompt treatment. Figure 1: Lytic lesion of the occipital bone. Figure 2: Numerous hepatic lesions consistent with metastatic disease. References Coiffier B, Altman A, Pui CH, et al. Guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review. J Clin Oncol 2008; 26:2767 Cairo MS, Bishop M. Tumor lysis syndrome: new therapeutic strategies and classification. Br J Haematol 2004; 127:3 Sklarin NT, Markham M. Spontaneous recurrent tumor lysis syndrome in breast cancer. Am J Clin Oncol 1995; 18:71. Baeksgaard L, Sorensen JB. Acute tumor lysis syndrome in solid tumors – a case report and review of the literature. Cancer Chemother Pharmcol 2003; 51:187. Cairo-Bishop criteria for TLS Element Value Uric Acid >8.0 mg/dL Calcium <7.0 mg/dL >6.0 mmol/L Phosphorus >6.5 mg/dL (children) >4.5 mg/dL (adults) Deranged Elements Element Value Uric Acid 12.1 mg/dL Calcium 6.9 mg/dL Potassium 4.8 mmol/L Phosphorus 4.1 mg/dL (adults) Table 1: Cairo-Bishop definition of laboratory tumor lysis syndrome (2). Table 2: Laboratory results during patient’s hospitalization