Figure 4. Adipophilin immunostain in BL and not-BL cases.

(A) BL is characterized by medium-sized cells with a monotonous cohesive pattern of growth, round nuclei with finely clumped and dispersed chromatin, a high proliferation rate and “starry-sky” appearance [Haematoxilin-eosin (H&E), original magnification (O.M.) ×200). (B) Neoplastic cells show strong positivity to adipophilin with single or multiple droplets in the cytoplasm, sometimes clustering the outer nuclear membrane (inset); the internal positive control is represented by macrophages which show granular positivity in the cytoplasm (arrows) (Adipophilin stain, O.M. ×200; inset, O.M. ×400). (C) An aggressive B-cell lymphoma with diffuse proliferation of medium- to large-sized cells with irregular nuclear contours and relatively large nucleoli corresponding to morphological score 1 according to the Naresh et al. scoring system is shown. Few small lymphocytes and starry-sky macrophages are also present (H&E, O.M. ×200). (D) Adipophilin immunostain on the case depicted in figure C with neoplastic cells showing weak positivity characterized by singly scattered fine lipid droplets in the cytoplasm (Adipophilin stain, O.M. ×200). (E) Morphological features of a diffuse large B-cell lymphoma (H&E, O.M. ×200). (F) Adipophilin immunostain on the case depicted in figure E is entirely negative (Adipophilin stain, O.M. ×200).