Relapsing Polychondritis With Increased Bone Marrow Signal on Magnetic Resonance Imaging in a 13-Year-Old Girl
Relapsing polychondritis (RPC) is an inflammatory disorder predominantly affecting cartilaginous structures including ears, nose, joints, and respiratory tracts. Although RPC is rare in children, previous reports indicated childhood RPC is atypical or severe. A 13-year-old girl presented with redness and swelling of the bilateral auricles and subsequently developed arthralgia of multiple joints. Histopathologic findings of the auricular cartilages were compatible with RPC. Magnetic resonance imaging (MRI) for the evaluation of arthralgia unexpectedly demonstrated increased bone marrow signal of metacarpals and the distal epiphysis of radii and ulnae. Although arthritis in RPC has not been well evaluated with magnetic resonance imaging, increased bone marrow signal has been reported in a child with RPC without an underlying disease. Thus, this could be another finding of RPC itself. Evaluation of more patients with magnetic resonance imaging would elucidate if this is an additional atypical finding of childhood RPC.
Relapsing polychondritis (RPC) is a rare inflammatory disorder that predominantly affects cartilaginous structures throughout the body, particularly ears, nose, eyes, joints, and respiratory tracts.1 Some patients with RPC were demonstrated to have serum autoantibodies against type II collagen or matrillin-1 that are expressed in chondrocytes,1,2 indicating autoimmune-mediated mechanisms of the development of chondritis. Relapsing polychondritis is also observed in association with other underlying diseases such as myelodysplastic syndrome, systemic vasculitis, or other autoimmune disorders,1–3 which makes extensive differential diagnosis indispensable. Clinical features and courses are variable, and there are no parameters available to predict the prognosis of each patient. Although RPC is especially rare in childhood, case reports and reviews indicated clinical manifestations of childhood RPC are likely to be severe or atypical: frequent respiratory tract involvement, symptomatic costochondritis, and an atypical pattern of persistent and destructive arthritis.4,5 Although there have been limited reports of RPC patients in which arthritis was evaluated by MRI,4,6,7 increased bone marrow signal was demonstrated on MRI in a 4-year-old girl with RPC without an underlying disease.4 Here, we describe a 13-year-old girl with RPC without an underlying disease who also had increased bone marrow signal on MRI, indicating this could be another clinical finding of RPC itself.