Extramedullary acute myeloid leukemia (AML) is a leukemic infiltration outside the bone marrow and is common in monocytic and myelomonocytic leukemia. The incidence is rare (0.6%-7.4%) and the clinical diagnosis requires a high index of suspicion. Fluorodeoxyglucose-positron emission tomography (FDG-PET) is used to detect, stage, and restage solid tumors, including lymphomas and Richter transformation. However its role in the management of liquid tumors and specifically in extramedullary AML has not been assessed. We present a case of a 64-year-old man who was diagnosed with AML and subsequently had recurrent extramedullary AML relapses. This case demonstrates the usefulness of FDG-PET for staging and assessment of the treatment response.