Spontaneous tumor lysis syndrome in the setting of small cell lung cancer: Report of two cases and review of the literature

Tumor lysis syndrome (TLS) is a life-threatening condition characterized by massive lysis of malignant cells after treatment, which results in hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia. These metabolic abnormalities may cause acute kidney injury (AKI), seizures, cardiac arrhythmia and sudden death. Spontaneous TLS (STLS), which occurs in the absence of chemotherapy or radiotherapy, is a rare entity that has particularly been described in the setting of hematological malignancies. STLS has been exceptionally associated with solid tumors; however it could be an underdiagnosed entity and should certainly be considered in the differential diagnosis of AKI in patients with solid tumors. Moreover, due to further delay in diagnosis this entity could be associated with worse prognosis. Early management with intravenous hydration, hypouricemic agents and correction of electrolyte disorders are essential, although clinical course may be aggressive.We describe two unusual cases of STLS in the setting of small cell lung cancer who developed STLS. A high index of suspicion is needed in order to initiate necessary prophylactic precautions and avoid fatal consequences.