Fig. 1 | Modern Pathology

Fig. 1

From: Focal Rosai–Dorfman disease coexisting with lymphoma in the same anatomic site: a localized histiocytic proliferation associated with MAPK/ERK pathway activation

Fig. 1

Focal Rosai–Dorfman disease coexisting with nodular lymphocyte predominant Hodgkin lymphoma (cases 1 and 2). (a, case 1) Low-power view of a lymph node involved by nodular lymphocyte predominant Hodgkin lymphoma and a microscopic focus of Rosai–Dorfman disease (20 × , arrow). (b, case 1) High-power magnification of histiocytes engulfing numerous leukocytes (400 × ). This case is positive for p-ERK by immunohistochemistry (inset, 1000 × ). (c, case 2) Low-power image of a lymph node involved by nodular lymphocyte predominant Hodgkin lymphoma and multiple microscopic clusters of Rosai–Dorfman disease surrounding lymphoid nodules (20 × ). (d, case 2) High-power magnification of histiocytes undergoing emperipolesis (400 × ). This case is positive for p-ERK by immunohistochemistry (Inset, 1000 × )

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