Upper humeral cortical thickness as an indicator of osteopenia: diagnostic significance in solitary myeloma of bone.

Solitary myeloma of bone is a form of plasma cell tumor, histologically indistinguishable from multiple myeloma but characterised by a single bony focus of disease. Most patients respond to local radiotherapy (median survival 10-12 years); however, many (greater than 30%) rapidly develop multiple myeloma (median survival 2-4 years). Currently, no criteria exist for identifying these high-risk patients at the time of diagnosis. We have assessed the prognostic value of clinical features at presentation in 32 patients with solitary myeloma of bone. Only osteopenia at presentation (P less than 0.000003) and immunoparesis (P less than 0.00002) proved to be independent, significant prognosticators of decreased survival. Exclusion of patients with osteopenia or immunoparesis at presentation identified a group with an 80%-90% chance of surviving 10 years. Patients with either risk factor had a median survival of only 27 months. Osteopenia was assessed using measurements of combined cortical thickness in the upper humerus. This site has not previously been used, and normal values are presented for a control group (n = 413).