Isolated periostitis as a manifestation of systemic vasculitis in a child: imaging features.

We report a case of isolated periostitis associated with Takayasu arteritis in a 10-year-old boy presenting with calf pain. Radiographs revealed a localized, thick periosteal reaction with irregular margin in the proximal left fibula. MRI revealed irregular thickening with enhancement of the periosteum in the proximal fibula and heterogeneous enhancement along vascular bundles in the calf. Isolated periostitis is a rare skeletal manifestation of systemic vasculitis that could be misdiagnosed as neoplastic or traumatic periosteal reaction.