Imaging features of periostitis as a manifestation of IgA vasculitis: A case report

INTRODUCTION: Periostitis in systemic vasculitis is very rare with only a few previously reported cases. The reported cases were seen in polyarteritis nodosa or Takayasu arteritis. We report the first case of periostitis associated with IgA vasculitis with demonstration of computed tomography (CT), magnetic resonance imaging (MRI) features, and serial changes of radiographs. PATIENT CONCERNS: A 74-year-old man visited an orthopedic outpatient clinic for pain in both lower legs and left ankle pain. He underwent a total ankle arthroplasty of the left ankle 3 years ago. His medical history disclosed IgA vasculitis/nephropathy caused by cephalosporin antibiotic class 5 months earlier. Plain radiography, MRI of the right lower leg, CT scan of the left ankle showed single lamellar to spiculated periosteal reactions at both tibia, fibula and left calcaneus. There was no evidence of bone or soft tissue mass lesions or cortical destruction. DIAGNOSIS: We concluded that this was a case of periosteal reactions associated with IgA vasculitis for the following reasons: (1) periosteal biopsy was negative for tumor. (2) there was no pulmonary lesion on chest radiography and CT, no history of trauma, inflammatory arthritis, metabolic disease, or genetic disease that could cause periostitis at multiple bones, (3) the initial MRI showed predominant signal changes around the tibial and fibular shafts, possibly explaining subsequent periosteal reactions, and (4) symptoms subsided with conservative treatment and follow-up radiographs showed remodeling of periosteal reactions. INTERVENTIONS: The patient took conservative management. OUTCOMES: His calf pain improved, and a radiograph 7 months later showed remodeling to the solid or single lamellar periosteal reaction along the both tibia and left fibula. CONCLUSION: Awareness of this uncommon manifestation would help differential diagnosis of periostitis and could help decrease the patient's anxiety. It should also be noted that periosteal reactions by benign entities could cause aggressive-looking periosteal reactions in post-operative regions.