Fig. 5

Mononuclear or binuclear Reed-Sternberg (R-S) cell-like large cells (arrows) are scattered in a background composed of lymphocytes and histiocytes, which resembles classical Hodgkin’s lymphoma a, b. Low- and high-power views show the typical histology of FDCS, which consists of ovoid- to spindle-shaped cells in a storiform pattern (c, d). In some regions, the transition between the areas, such as those of classical Hodgkin’s lymphoma and those with the typical morphology of FDCS, can be found (e), both of which are positive for CD21 (f)