SDC1 and cholesteryl ester measurement: The introduction of immunohistochemistry for CD138 (IHC-CD138) markedly (odds ratio: 2.8) improved the sensitivity (100% vs. 75%), specificity (100% vs. 65%), interobserver variability (96% vs. 68%), and intraobserver variability (93% vs. 47%) in the histopathologic diagnosis of CE [24,25].