Fig. 2.

Immunohistochemistry for CD68 in 0.5 cm (a), 1 cm (b), 2 cm (c) and 3 cm (d) RMM nodules; CD68⁺ cells have uniform distribution throughout tissues. Immunohistochemistry for CD163 in 0.5 cm (e), 1 cm (f), 2 cm (g) and 3 cm (h) shows uniform distribution of CD163⁺ cells throughout tissues. Immunohistochemistry for MHC class II in 0.5 cm (i), 1 cm (j), 2 cm (k) and 3 cm (l) nodules shows abundant staining in marginal tumor areas. In 2 cm (m) and 3 cm (n) nodules, clusters of MHC class II⁺ cells (black dotted line) or areas with few positive cells (blue dotted line) are seen in central tumor areas. Bars: A-L, 50 μm; M, N, 100 μm