Adipocyte-Like Differentiation in a Posttreatment Embryonal Rhabdomyosarcoma

Figure 2

Histochemical and immunohistochemical studies in posttreatment rhabdomyosarcoma. (a) Microscopic appearance of resected tumor after adjuvant chemotherapy, demonstrating diffuse sheets of round tumor cells (H&E, ×200 original magnification) and (b) vacuolated adipocyte-like cells (H&E, ×400 original magnification). (c) Adipophilin demonstrates strong membrane staining within adipocyte-like cells (adipophilin immunostain, ×100 original magnification). (d) Oil Red O histochemical stain highlights intracytoplasmic lipid within the adipocyte-like cells (Oil Red O, ×200 original magnification). (e) The adipocyte-like cells stain with S-100 protein (S-100 protein immunostain, ×400 original magnification). (f) A subset of vacuolated adipcoyte-like cells show focal cytoplasmic desmin positivity (desmin immunostain, ×400 original magnification) but myogenin (g) is negative in vacuolated cells, staining only the nuclei of rhabdomyoblasts (myogenin immunostain, ×400 original magnification).

(a)

(b)

(c)

(d)

(e)

(f)

(g)