PMC5836236_01
Lymph node enlargement. a Postauricular. b Left inguinal.
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F1
Widespread lymph node enlargement was observed in the head and neck region, as well as the presence of bilateral axillary nodes, and inguinal nodes (Fig. 1).
Bone marrow aspirate showing plasma cells actively producing immunoglobulins "Mott cells" (a) and hemophagocytosis of RBC and neutrophils (b).
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F2
The bone marrow aspirate revealed reactive hypercellular bone marrow with Mott cells (active plasma cells) and abnormal histiocytes with a high hemophagocytic activity (Fig. 2).
Lymph node biopsy showing: large histiocytes with emperipolesis (black arrows) and plasma cells with large inclusions containing immunoglobulins "Russel body" (yellow arrow) (a); immunohistochemical staining of lymph node biopsy, positive for S100 (b); immunohistochemical staining of lymph node biopsy, positive for CD68 (c); immunohistochemical staining of lymph node biopsy, negative for CD1a (d); and immunohistochemical staining of lymph node biopsy, negative for CD21 (e).
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F3
A lymph node biopsy from the anterior cervical group (Fig. 3) showed that the sinusoids were extended and filled with S100 and CD68-positive but CD1a-negative histiocytes with abundant cytoplasmic fat globules and exhibited emperipolesis (viable lymphocytes inside the cytoplasm of histiocytes).