RESUMO
BACKGROUND: Prevalence of extramedullary disease (EMD) in acute myeloid leukemia (AML) at the time of diagnosis is unknown. Previous estimates range from 2.5% to 30.5% and are usually based on clinical examination. This may cause an under diagnosis of EMD as not all extramedullary manifestations are easily detectable. Few recent studies have used positron emission tomography (PET) scans for diagnosing EMD in patients AML. METHOD: During a 9-month period, newly diagnosed patients with AML who were candidates for intensive chemotherapy were 18F-Fluoro-deoxy-glucose (FDG) PET-scanned prior to induction treatment. We compared the prevalence of EMD diagnosed by PET scans and by clinical examination. Subsequent PET scans following induction chemotherapy were performed for response evaluation of EMD. RESULTS: Twenty-six patients were included in the study. 18-F-FDG PET scans revealed more than twice as many patients with EMD than found by clinical examination (65% vs. 31%). PET demonstrated 55 EMD lesions compared with 15 diagnosed by clinical examination. In general, the responses of EMD detected by PET scans were concordant with the bone marrow responses assessed by pathology examination. CONCLUSION: 18-F-FDG PET is a useful tool for diagnosing EMD in AML and for assessing treatment responses of EMD in AML.
