Popliteal Cysts in Chronic Hemodialysis Patients

Dr. L. Baldrati, Servizio di Nefrologia e Dialisi, Ospedale M. Bufalini, Via Ghirotti 286, I-47023 Cesena (Italy) Dear Sir, The development of popliteal tumors has recently been reported as a possible manifestation of dialysis-related amyloidosis [1, 2]. This prompted us to carry out a clinical and radiological (ultrasonography and/or CT scan) screening in our hemodialysis patients who were on treatment for more than 60 months. 28 patients were eligible for the investigation; at the time of the study, they had been dialyzed for 127 ± 40 months and solely or mainly cuprophan membranes had been used in all. 11 popliteal masses (maximum diameters 9×5 cm) were detected in 6 (21.4%) of these patients. Table 1 reports the characteristics of these patients; as shown, all suffered from some of the major features of dialysis-related amyloidosis. 10 of the 11 masses were filled with a fluid material, whereas the remaining one appeared dense and partly calcified. In the 3 patients who were investigated by CT scan, cysts could be demonstrated to communicate with the joint cavity (Baker’s cysts) (fig. 1). In 1 of these 3 patients, immunocytochemical analysis Fig. 1. CT scan view of popliteal cysts (patient 3). Both knees were affected and both cysts are demonstrated to communicate with the respective joint cavity. demonstrated diffuse ß2-microglobulin-amyloid deposition within the synovial wall of the surgically removed cyst. Interestingly, in this patient a ß2-microglobulin-pos-itive synovitis of the same knee had been demonstrated Table 1. Clinical and radiological features of the patients