Solitary myeloma: clinical and prognostic features of a review of 114 cases.

Within plasma cell disorders, solitary myeloma is rare as compared with multiple myeloma. In order to evaluate their relationship, the clinical findings for 114 patients with solitary myeloma were compared with those for 70 patients having classic multiple myeloma. The period of follow up ranged from a few weeks to twenty-four years, and 68.5% of those with solitary myeloma alive at ten years. Although only 23% of patients with solitary myeloma had local or widespread recurrence after two years, at ten years 85% had experienced disease progression. Comparison of the 85% with disease progression with patients with multiple myeloma revealed that solitary myeloma occurred at a younger age (mean 52.1 years), more frequently in men (60.5%), less commonly with initial spinal involvement (61.8%), but more commonly with neurologic problems associated with spinal involvement (25%), and that much more commonly, no monoclonal component was detectable in serum and/or urine at the time of initial diagnosis (82.5%). There were only two significant differences between those patients with (85%) and without (15%) progression at ten years; the patients were younger (mean, 45.7 years) and spinal involvement (26.7%). However, was less common among patients without progression, and component monoclonal always disappeared following treatment with surgery and/or radiation therapy. It is thus concluded that solitary myeloma and multiple myeloma are clearly different clinical entities; however, most patients with solitary myeloma do eventually have multiple myeloma.