SYSTEMIC CONNECTIVE TISSUE DISEASE COMPLICATED BY CASTLEMAN'S DISEASE: REPORT OF A CASE AND REVIEW OF THE LITERATURE

Background and objective. Castleman’s disease represents an atypical lymphoproliferative disorder characterized by the prevalence of B CD5-positive cells in the marginal zone. The occurrence of autoimmune manifestations has often been reported,but the associations of Castleman’s disease with systemic autoimmune syndromes has been rarely described. Otherwise, many authors stressed the difficulties in distinguishing between connective tissue disease and Castleman’s disease in most cases. To clarify this issue, we describe a patient and collected from the literature all cases of Castleman’s disease associated to a connective tissue disease. Case report. A 19 years old woman presented with autoimmune thyroiditis and polimyositis. Seven years after the onset she developed a systemic inflammatory flare and a burst of autoimmunity, followed by generalised lymphoadenopathy. A mediastinal lymph node biopsy led to the diagnosis of Castleman disease of the mixed type. Chemotherapy was performed, with rapid response on the lymphoproliferative disorder but with persistence of underlying autoimmune disorder. The plasmatic dosage of B-lymphocyte stimulator (BLyS) was high (13.3 ng/mL) at diagnosis of Castleman’s disease. It fell down dramatically after chemotherapy (4.97 ng/mL), even though it remained only just over the mean BLyS value found in healthy blood donors (3.37±0.78- ng/mL). Comment. Castleman’s disease can present autoimmune traits. In our patient, Castleman’s disease complicated the course of a connective tissue disorder several years after the onset. We hypothesize that the chronic stimulation of B cell clones, particularly CD5+, by BLyS could favour the development of both autoimmune diseases and a broad range of lymphoproliferative disorders (such as Castleman’s disease). This is the first report of increased BLyS levels in a patient with Castleman’s disease, supporting a possible pathogenetic role of BLyS in the development of an autoimmune disorder and of a B lymphoproliferative disorder years later.