Rapid skeletal turnover and hypercalcemia associated with markedly elevated interleukin-6 levels in a young black man.

A 24-year-old black man presented with diffuse musculoskeletal pain and shotty lymphadenopathy. Laboratory studies revealed hypercalcemia and hyperphosphatemia, very high serum alkaline phosphatase activity, diffuse but intense uptake of radionuclide on a bone scan, urinary N-telopeptide excretion 30 times the upper limit of normal, and serum interleukin-6 100 times the upper limit of normal. An extensive workup for etiologies of the disorder was negative. A bone biopsy revealed intense osteoclastic resorption coupled with rapid bone formation and/or remodeling. This case appears to represent a new entity. Treatment with bisphosphonates produced symptomatic and biochemical improvement.