Background: This case report describes a spontaneous tumor lysis syndrome due to a rare solid tumor.
Case presentation: A 65-year-old white woman had tumor lysis syndrome, which represent a dangerous oncological emergency. This syndrome occurs usually with a hematological tumor, but in this case our patient had a solid tumor, which was a rare extraskeletal osteosarcoma, localized in her pelvic region. She also had lung metastases and bilateral hydronephrosis. After spontaneous tumor lysis syndrome, she had acute renal insufficiency, which was treated with hemodialysis and successively with rasburicase, Kayexalate (sodium polystyrene sulfonate), and febuxostat.
Conclusion: Tumor lysis syndrome represents an oncological emergency, which must be suspected and treated as soon as possible.
Keywords: Case report; Kalemia; Osteosarcoma; Rasburicase; Tumor lysis; Uricemia.