Tumor lysis syndrome after bortezomib therapy for plasma cell leukemia.

Tumor lysis syndrome (TLS) is a manifestation of metabolic disturbances that can lead to severe treatment complications and ultimately life-threatening events. This syndrome has been reported in solid tumors but is more common in bulky, hyperproliferative malignancies. Tumor lysis syndrome in plasma cell malignancies is less common due to the low turnover rate of the malignant B cells. Bortezomib is the first proteasome inhibitor approved by the United States Food and Drug Administration as second- and third-line therapy for patients with relapsed multiple myeloma. We describe the case of a patient with plasma cell leukemia treated with bortezomib who developed TLS. Bortezomib was begun as single-agent therapy that resulted in the development of TLS after the third dose of the first cycle. Evaluation with the Naranjo Adverse Drug Reaction Probability Scale indicated a probable relationship between TLS and bortezomib in this patient. Patients receiving bortezomib may be at risk for TLS, especially if they have high tumor burden, rapidly proliferative disease, and unfavorable cytogenetics.