Erythroblastic synartesis in a patient with small lymphocytic lymphoma

Abstract

A 70-year-old patient was admitted with severe hypochromic microcytic anaemia with reticulocytopenia. The blood count showed a haemoglobin level of 49 g/l (MCV 73AE8 fl, MCH 22AE8 pg), white blood cell count of 6 · 10/l (normal differential) and platelet count of 440 · 10/l. The absolute reticulocyte count was 1AE5 · 10/l. The serum ferritin, vitamin B12 and folate levels were normal. A bone marrow aspiration and trephine biopsy were performed, including cytogenetic and flow cytometry analysis. The aspirate revealed striking erythroblastic hyperplasia and dyserythropoiesis with clusters of closely linked erythroid cells. At the intercellular junction of the erythroblasts, a clear non-basophilic zone was evident (Figs). The findings were diagnostic of erythroblastic synartesis. Furthermore, there were an increased number of lymphocytes in the marrow comprising 23% of nucleated cells. The trephine biopsy and flow cytometry confirmed the presence of a CD5+, CD19+, CD23+ low grade lymphoma (small lymphocytic lymphoma) infiltrating the marrow. Cytogenetic analysis was normal. Whole body computed tomography scans demonstrated intraabdominal lymphadenopathy and serum protein electrophoresis identified a monoclonal IgGj band (1AE5 g/l). Erythroblastic synartesis was first described in 1973 by Breton-Gorius et al in a patient with an acquired dyserythropoietic anaemia who died of haemochromatosis because of long-term transfusions. In that case, electron microscopy revealed junctions between erythroblasts formed by interdigitating cell processes. The new phenomenon was named ‘erythroblastic synartesis’, from the Greek words ‘rtm’ (with) and ‘ aqsgriV’ (link). This condition is a rare form of acquired autoimmune dyserythropoiesis that leads to ineffective erythropoiesis and accompanies lymphoproliferative and autoimmune disorders. Studies indicate that a monoclonal serum immunoglobulin (IgGj in our case) directed against an adhesive receptor of the erythroblast membrane is responsible for the dyserythropoiesis. Treatment of the underlying autoimmune or lymphoproliferative disease, as experienced with our patient, leads to correction of dyserythropoiesis and restoration of a normal haemoglobin level.