Objective: To determine whether there are peculiarities of the POEMS syndrome (a multisystemic disorder associated with polyneuropathy, organomegaly, endocrinopathy of various forms, production of a monoclonal [M] component, and skin changes) in Caucasian patients, especially signs and symptoms absent in other series; and to attempt a reappraisal of the neuropathy and endocrinopathy to find a unifying mechanism.
Design: A retrospective, cooperative study compared 25 cases, observed over a 15-year period, with two published series of patients, one of Japanese patients and one of American patients, and with a review of the literature on non-Asian cases. Details were obtained of patients' medical history, physical examination, immunochemical and hormonal testing, roentgenographic examination, computed tomography imaging, and electromyography.
Results: The main features of the syndrome found in these patients were those first described in Japan: polyneuropathy, enlargement of the lymph nodes, liver, and spleen, endocrine disturbances, low concentration of the monoclonal component, hyperpigmentation, and hypertrichosis. Three other symptoms were found more frequently than previously reported: skin angiomas, scleroderma changes of the hands, and thrombocytosis. Electromyography and nerve biopsy showed a variety of abnormalities ranging from demyelination to axonal degeneration. Nerve deposits of immunoglobulin were absent. Organomegaly seemed to be heterogeneous. Pathologic findings in the enlarged lymph nodes and spleen were compatible with Castleman's disease. Liver biopsies were usually normal. The endocrine changes were surprisingly diverse, with some observations combining unrelated primary and secondary insufficiencies. No single hypothesis emerged regarding their mechanism. All M components had a lambda-light chain. An IgG M component was found more frequently in solitary lesions. An IgA M component was found more frequently in patients without bone lesions. Sedimentation rate was usually normal. Radiotherapy of solitary plasma-cytomas was followed by dramatic improvement of extramedullary signs and symptoms in all cases.
Conclusions: The symptoms, clinical course, and management of the patients reported here were similar to those observed in the literature. This study confirms the existence of a close link between symptoms and lambda-light-chain production. There are indications that a plasma cell growth factor that does not cross-react with interleukin-6 (IL-6) may be involved.