Extraskeletal calcification is frequent and severe complication in patients with end stage renal disease (ESRD). Uremic tumoral calcinosis (UTC) is the massive calcium deposits in periarticular tissues, usually around large joints. This complication is thought to be related to hyperphosphatemia and the high calcium–phosphorus product as well as development of secondary hyperparathyroidism (SHPT) in patients on long–term dialysis.The aim of this study was to detect the incidence, most prevalent localization, and distinguishing features of the UTC in dialysis patients by using ultrasound. Soft tissues and joints were studied in 124 patients with ESRD on dialysis. Average length of dialysis treatment was 76 months ranging from 0.5 to 230 months. Extraskeletal calcification of the periarticular tissues characterized as UTC was found in 6 patients (4.8 %). In four patients this complication developed concurrent with the SHPT, in two other patients there were low levels of parathyroid hormone and significant hyperphosphatemia with high calcium-phosphorus product. In general, multifocal calcification was noted with several involved areas. Using ultrasound, UTC appeared as calcified masses in periarticular tissues with cystic lesions characterized by thick hyperechogenic walls measuring 1.5–20 cm in length and 1.0–15.0 cm in width. Echogenic sediment was present within the cysts. Hypervascularity was noted surrounding the calcified masses.These masses were thought to be the calcified content of the synovial bursa and surrounding soft tissue with incapsulated calcium-containing fluid. Liquid component and hypervascularity were indicative of the active process. In one patient, masses significantly regressed in size following the removal of enlarged parathyroid glands. Given pronounced calcification with joint movement limitation, two patients had their calcified masses removed. During the procedure, multiloculated, calcium–containing thick–walled cysts were found. Histologic analysis of the obtained tissue revealed fibrous connective tissue, multiple irregular shaped large and medium size amorphic loci with calcium salt deposits. These loci were walled by significant macrophage infiltration and surrounded by multiple multinuclear foreign body giant cells. Ultrasound method is highly informative in diagnosis of the extraskeletal calcification of the periarticular tissues in dialysis patients allowing detecting the presence, extent, and activity of the metabolic process.
