We present a case of human T-cell lymphotropic virus, type 1 (HTLV-1)-associated myelopathy, also known as tropical spastic paresis. While the literature has previously described the neuroradiological findings of spinal atrophy and hyperintense T2 lesions involving the cerebral white matter, little information is available about musculoskeletal imaging findings. Our patient demonstrated diffuse muscle atrophy of the thigh muscles, particularly the posteromedial groups. Our case supports HTLV-1-associated myelopathy as a disease of neurological etiology with resulting muscular denervation.