Table 2.

Teaching points

1. MM-associated Ig LC crystalline cast nephropathy was classified into tubular crystalline nephropathy (type 2) in the recent classification of crystalline nephropathies.

2. This nephropathy is a rare but distinct variant form of myeloma cast nephropathy.

3. Clinicopathologic characteristics of this nephropathy are rapid progression and poor outcomes, λ LC dominance, crystalline cast formation both in the proximal and distal tubular lumens, and with or without incorporation of THP in distal tubular casts.

4. Early diagnosis and chemotherapy for MM in the new era can improve the prognosis of this nephropathy.

5. Cast formation in this nephropathy may depend on structural characteristics of the disease-causing BJP.

BJP, Bence–Jones protein; LC, light chain; MM, multiple myeloma; THP, Tamm–Horsfall glycoprotein.