We describe a 65-year-old man who presented with 'aches and pains' localized to the lower extremities, and was diagnosed with acute myeloid leukemia (AML). We hypothesize that this case represents an atypical presentation of AML with an immune-mediated necrotizing-like myopathy as a possible paraneoplastic manifestation of the disease, which improved after initiating chemotherapy. Our patient received a full course of 7 + 3 chemotherapy with cytarabine and daunorubicin. Proximal leg weakness and pain improved markedly following this treatment, establishing a temporal relationship between the possible paraneoplastic manifestation and treatment of underlying disease. Associations between malignancy and myopathies such as polymyositis and dermatomyositis have been well established in the literature. However, paraneoplastic IMNM is still a rare clinical phenomenon and has infrequently been associated with AML. This case may suggest myopathy and associated muscle 'aches and pains' as possible presenting symptoms of underlying AML, highlighting the heterogeneity of the clinical manifestations of this disease.
Keywords: Acute myeloid leukemia; Idiopathic inflammatory myopathy; Immune-mediated necrotizing myopathy.