(a)
(b)
(c)
(d)
Figure 2: Permanent sections showing histology of Rosai-Dorfman disease; low power 100x (a) and high power 400x (b) hematoxylin and eosin stain showing histiocytic infiltrate. Blue arrow indicates emperipolesis. Positive immunostaining for CD68 (c) and S100 (d).