Figure 1.

Clinical and histological characteristics of the case. (A) Cervical node enlargement at diagnosis. (B) PET-CT scan at diagnosis showing bilateral hyper-metabolic cervical node lesions. (C) Spontaneous decrease in size and metabolism of the previous lesions after eight months of watchful waiting. (D) The lymph node that was biopsied had a preserved architecture, with a massive sinusoidal dilation that contained large plurinucleated histiocytes with large pale nuclei and large nucleoli (H&E stain, original magnification ×40). (E) Emperipolesis lesions were abundant (black arrow), with lymphocytes or plasma cells engulfed within the cytoplasm of histiocytes (H&E stain, ×200). (F) Immunohistochemistry showed strong S100 positivity of histiocytes (×200).