A Case of Paget's Disease of Bone Associated with Hypomyopathic Dermatomyositis.

Dermatomyositis is associated with malignancies and is known to have systemic involvement. However, associations with bone diseases have not been well described in the current literature. This article describes the second reported case of the co-existence of dermatomyositis and Paget's Disease of Bone (PDB), but is the first report to describe such co-existence in a specific subtype of dermatomyositis - hypomyopathic dermatomyositis. Our patient was a 51-year-old woman who presented with prolonged fever, myalgia, morning stiffness, and rashes pathognomonic of dermatomyositis. There was no muscle weakness clinically, although muscle enzymes were raised and electromyogram revealed myopathic changes. Further imaging showed the incidental finding of a T11 vertebral bone lesion, of which biopsy confirmed the diagnosis of PDB. Our report illustrates the diagnostic approach to bone lesions in patients with dermatomyositis, and takes a closer look at the pathophysiology and management implications of the co-occurrence of these two rare diseases.