Abstract
Tumor lysis syndrome (TLS) refers to a constellation of metabolic abnormalities that result from release of intracellular solutes (potassium, phosphate, and nucleic acid metabolites) from rapidly dying tumor cells. While TLS most commonly occurs following chemotherapy, spontaneous TLS can rarely occur in rapidly dividing liquid or solid malignancies. Here, we report the cases of two patients who presented with non-specific symptoms and were found to have spontaneous TLS. Work-up in both cases led to a diagnosis of T-cell malignancy (i.e., acute lymphoblastic leukemia and angioimmunoblastic lymphoma). Given that spontaneous TLS can be the first manifestation of an underlying malignancy, all physicians should be familiar with this oncologic emergency. Early recognition and prompt management can be lifesaving for patients with an otherwise curable malignancy.