title: Adipocyte-Like Differentiation in a Posttreatment Embryonal Rhabdomyosarcoma.
abstract: We describe a 16-year-old boy with rhabdomyosarcoma, consistent with embryonal subtype, of the lower extremity who received systemic neoadjuvant chemotherapy and subsequent excision. Microscopic sections of the postchemotherapy excision demonstrated diffuse, prominent, and immature adipocyte-like differentiation, in addition to skeletal muscle differentiation. Adipocyte-like differentiation was confirmed by a combination of positive Oil Red O and adipophilin immunohistochemical staining. To our knowledge, this represents the first report of an unusual phenomenon of differentiation of a soft tissue rhabdomyosarcoma into adipocyte-like cells after chemotherapy.
authors.affiliation: Department of Pathology, University of California, San Francisco, 505 Parnassus, M580, San Francisco, CA 94143, USA.
authors.forename: Dana
authors.initials: D
authors.lastname: Balitzer
authors.affiliation: Departments of Pathology and Dermatology, University of California, San Francisco, 1701 Divisadero Street, Suite 280, San Francisco, CA 94115, USA.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: McCalmont
authors.affiliation: Department of Pathology, University of California, San Francisco, 1825 4th Street, M2354, San Francisco, CA 94143, USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Horvai