Average grade for histopathologic features for each subtype of iMCD. Average grades for regressed germinal centers, FDC prominence, vascularity, plasmacytosis, and hyperplastic germinal centers in hypervascular, plasmacytic, and mixed subtypes of iMCD as well as cases determined to not be CD (not CD) as assessed by hematopathologic review. See Figure 3 for the grading scale for each feature. The bars depict average grades for histopathologic features for a given subtype with mean ± standard error.