Up to 50% of patients with end-stage renal disease will develop mitral valve calcification (Figure 2).4 Large, polypoid calcific deposits occur at the anterior and posterior leaflet bases, sparing the free edges and chordae tendinae; this differs from senile degenerative mitral valve calcification, which usually demonstrates smaller nodules or ridges posteriorly and rarely affects the anterior leaflet. With UTC, mitral annular calcification may also develop, resulting in clinically significant stenosis or regurgitation.5 The differential diagnosis of soft tissue calcification includes myositis ossificans, heterotopic ossification, scleroderma, sarcoidosis, and sarcomas involving bone, cartilage, or synovium.6 Radiography of affected joints demonstrates extraosseous, densely calcific masses. In this patient the left hip joint was draining “milky” material. In patients with UTC, this drainage is usually composed of calcium hydroxyapatite, along with calcium carbonate, calcium phosphate, and even calcium oxalate. Similar presentations can be seen with abscesses, crystalline arthropathies, or acute infectious arthritis. Aspiration and microscopy of the involved sites is mandatory. UTC will demonstrate whitish-yellow, pasty material that under light microscopy is amorphous and may contain psammoma body–like masses that are variably birefringent6; staining with alizarin S red may help identify these calcific bodies.