Non-secretory multiple myeloma: a report of 13 cases with a review of the literature.

The clinical features of 13 patients with non-secretory myeloma from a series of 172 consecutive multiple myelomas are presented. The non-secretors survived significantly longer that the secretors, median 46 months versus 21 months (p less than 0.01). Non-secretory myeloma was associated with a higher incidence of neurological presentation, minimal lytic bone disease, a lower median percentage of plasma cells in the marrow and a lower incidence of hypogammaglobulinaemia. The median survival of the non-secretors with minimal lytic bone lesions was 74 months compared to 21 months for those with extensive bone disease. The superior survival of non-secretors is thus thought to be due to earlier presentation possibly as a result of a tendency to form symptomatic local tumours. Retrospective immunoperoxidase staining of stored tissue was performed in nine cases. In only one of these was a monoclonal immunoglobulin not detected indicating that true 'non-production' is rare. In four patients who produced a biochemically detectable paraprotein during the course of their disease and in whom immunoperoxidase data was available the immunoglobulin was of the same type. Immunoperoxidase staining may help in the initial diagnosis of non-secretory myeloma but did not contribute any prognostic information.