Patchy FDG uptake on FDG PET/CT in a patient with vasculitic neuropathy in restricted lower‐limb vasculitis

Abstract

A 54‐year‐old man with diabetes mellitus presented with fever, pain, muscle weakness, and sensory disturbances in the lower limbs. His serum C‐reactive protein level was markedly increased; However, no autoantibodies, other than anti‐glutamic acid decarboxylase antibody, were detected. Nerve conduction studies revealed axonal polyneuropathy. 18F‐fluorodeoxyglucose positron emission tomography/computed tomography revealed patchy uptake patterns specific to restricted lower‐limb vasculitis. The muscle and nerve biopsy specimens suggested vasculitic neuropathy. Treatment with oral prednisolone and cyclophosphamide pulse therapy markedly improved his lower‐limb weakness and paresthesia. Clinicians should consider the involvement of vasculitic neuropathy, as well as myopathy, in patients with restricted lower‐limb vasculitis.