RESUMO
BACKGROUND: Tumor lysis syndrome can occur after treatment of fast-growing cancers. Early detection of tumor lysis is crucial to minimize the toxic effects on organs and potentially life-threatening complications. METHODS: A patient with acute monocytic leukemia presented with spurious thrombocytosis. A peripheral blood smear was stained with alpha-naphthyl butyrate esterase to discriminate tumor cell fragments from platelets. RESULTS: Peripheral blood smears showed widespread leukemic cell fragmentation. Tumor lysis syndrome (TLS) after treatment for acute monocytic leukemia was diagnosed. The patient underwent chemo- and radiotherapy followed by umbilical cord blood transplantation and remains symptom-free two years after transplantation. CONCLUSIONS: For patients with thrombocytosis accompanied by bizarre scatter-grams on automatic hematologic analyzers, further diagnostic procedures should be performed to determine the exact cause of thrombocytosis.