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 gcneralized 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, 1 1 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.
KFY WORDS Solitary plasmacytoma Paraproteincmia Myeloma years or more.' Many of these patients will eventually develop myeloma, and this has led some authors to speculate that SPB is simply an early stage of Others, however, point out that a significant proportion of patients with SPB remain disease-free for long periods after local treatment, with survival rates greater than 20 years being not uncommon.' Some patients with SPB progress to myeloma within 1-3 years and may well have occult disseminated disease at presentation. Because no single institution has been able to accumulate a large experience the diagnostic criteria and prognostic indicators for SPB remain poorly defined.4 Consequently, early recognition of those patients transforming to myeloma has proven difficult. Recently, generalized osteopenia and immunoparesis have been suggested as factors that identify a group of patients with SPB who develop myeloma early, and subsequently have reduced survival.]
The aim of this review was (i) to document the clinical features, treatment and survival of our patients, (ii) to review the diagnostic criteria for SPB and (iii) to try and identify factors predictive for early development of myeloma.