The patients were categorized in three subgroups of IPSID: alpha-chain disease (n=8), non-alpha chain disease with other monoclonal immunoglobulins (n=3), and polyclonal 'non-malignant' IPSID (n=2). In several patients the disease had unusual features, and this in some cases delayed the diagnosis. In suspected cases it is thus of the utmost importance to proceed to an exploratory laparatomy. Patients with stage C disease had a short survival, whereas two patients with stage A alpha-chain disease responded to treatment with cyclophosphamide, vincristine and prednisolone, and cyclophosphamide, doxorubicine, vincristine and prednisolone, respectively, have a disease-free long survival of 35 and 12 years, and appear to be cured.