[Gougerot-Sjögren syndrome, periarteritis nodosa, non-Hodgkin's lymphoplasmocytic lymphoma and acquired C4 deficiency].

A Sjögren syndrome was confirmed histologically in a 19 year old woman. Four years later, periarteritis nodosa (PAN) with characteristic vascular lesions on muscle biopsy occurred simultaneously with lymphatic hyperplasia comprising splenomegaly and polyadenopathy. The PAN was cured with corticosteroids and cyclophosphamide and the lymphadenopathy regressed. Several months after treatment was stopped the lymphadenopathy recurred which histologically resembled a malignant non-hodgkin lymphoplasmocytoma secreting an IgM kappa monoclonal immunonoglobulin. During the PAN and the establishment of the lymphoproliferative syndrome a severe C4 deficit was detected which disappeared after chemotherapy.