BACKGROUND: Tumor lysis syndrome (TLS) is an oncologic emergency resulting from the massive destruction of tumor cells after cytotoxic chemotherapy for chemosensitive malignancies with a high tumor burden. Its clinical manifestations include severe electrolyte disturbances, metabolic acidosis, acute renal failure secondary to urate deposition in the kidney, heart, and skeletal muscle, and nervous system dysfunction. We report an extremely rare case of spontaneous TLS (STLS) in idiopathic primary myelofibrosis (PMF).

CASE REPORT: A 51-year-old Korean man was admitted to our hospital with general weakness and left-side abdominal pain. The patient was diagnosed with acute urate nephropathy with hyperphosphatemia, hyperkalemia, hypocalcemia, and metabolic acidosis. Splenomegaly was accompanied by leukocytosis and a peripheral blood smear revealed immature granulocytes without blast cells. Bone marrow biopsy showed PMF. Initially, we presumed it was a spontaneous tumor lysis syndrome of PMF. We immediately performed emergency hemodialysis. We concluded that the patient, who had chronic hyperuricemia due to undiagnosed PMF, was recently admitted to the emergency room with STLS due to overwork and dehydration.

CONCLUSIONS: We present an extremely rare case of STLS in idiopathic PMF. The mechanism of chronic hyperuricemia in our case might be rapid cell turnover due to ineffective erythropoiesis of PMF.

Keywords: primary myelofibrosis, Tumor Lysis Syndrome, Uric Acid, hyperuricemia