Solitary plasmacytoma of bone: clinical features, treatment and survival.

Eleven patients with solitary plasmacytoma of bone were seen between 1978 and 1991. A retrospective review of the clinical features, treatment and survival of these patients was made with the aim of helping to define those at risk for early development of myeloma. Nine patients (82 per cent) had paraparoteinemia at diagnosis. Treatment consisted of local irradiation plus or minus surgery (nine patients) and surgery alone (two patients). No patient received adjuvant chemotherapy. One patient had evidence of both generalized osteopenia and immunoparesis, and progressed to myeloma within six months. Four patients (36 per cent) progressed to myeloma. All of these had paraprotein levels which continued to rise following initial treatment. Three patients died of myeloma at 12, 81 and 144 months and the other patient is alive with myeloma at 76 months. Patients without paraproteinemia at presentation or whose paraprotein decreased after treatment did not progress to myeloma. Three patients have been followed for 8, 11 and 19 years with no evidence of myeloma. Failure of paraprotein to clear after local treatment suggests occult disseminated disease and is predictive of later development of overt myeloma.