Severe heterotopic ossification after total hip arthroplasty in Schnitzler syndrome.

Schnitzler syndrome is a rare disorder characterized by monoclonal IgM gammopathy, urticaria, recurrent fever, evidence of inflammation, bone pain, and arthralgia. We present the case of a patient affected by Schnitzler syndrome who developed Della Valle type C heterotopic ossification after total hip arthroplasty. A relationship between the underlying syndrome and the considerable heterotopic ossification observed is compatible with the patient's clinical history and incidental findings.