A Rare Case of Spontaneous Tumor Lysis Syndrome in a Pulmonary Neuroendocrine Tumor

Tumor lysis syndrome (TLS) is a serious medical condition in which the lysis of tumor cells results in a variety of abnormalities, including elevated uric acid, potassium, and phosphorus, decreased calcium, seizures, arrhythmias, and acute kidney injury (AKI). TLS most often occurs in hematologic cancers and after chemotherapy, whereas cases that arise without chemotherapy are termed spontaneous TLS (STLS). In our case, an 81-year-old female with a past medical history of hypertension and chronic obstructive pulmonary disease (COPD) initially presented to the emergency department for left lower back pain that was later found to have been caused by a bony metastatic lesion secondary to a neuroendocrine tumor of the lung. Her hospital stay was complicated by a worsening AKI that was refractory to fluids and the discontinuation of nephrotoxic medications. A uric acid, urine studies, lactate dehydrogenase, and metabolic panel ruled out other causes of her kidney injury and ruled in a diagnosis of STLS. The patient's condition worsened until she required hemodialysis, which she rejected in favor of comfort care. The patient died 14 days after admission. In conclusion, despite the majority of TLS cases originating from hematologic malignancies and in response to chemotherapy, STLS should be considered in refractory AKI for cancer patients, even when secondary to solid tumors like neuroendocrine tumors of the lung.