Pathology. (A) Cytological appearances of BIA-ALCL cells on cytopsin preparation from an effusion (original magnification ×600; Giemsa stain). (B) Histological appearances of BIA-ALCL in capsulectomy specimen (original magnification ×400; hematoxylin and eosin stain). (C) CD30 expression by the neoplastic cells of BIA-ALCL (original magnification ×400; immunoperoxidase stain). (D) Foreign body giant cells reaction against silicone particulate shed from textured implant in the capsule. (original magnification ×400; hematoxylin and eosin stain) (E) Flow cytometric immunophenotyping of effusion from a case of BIA-ALCL. The neoplastic cells, shown with purple dots, express CD4 and CD2 (dim) (E) but not CD3 (F). They are brightly positive for CD30. Normal CD4 and CD8-positive T cells are shown in red and green, respectively. Small numbers of NK cells, shown by dark blue dots, are present. The remaining mononuclear cells, shown in gray dots, are mostly macrophages. All panels are gated on mononuclear cells. (G) The flow cytometric gate for CD30.