Botryoid Rhabdomyosarcoma : Cambium Layer
Microscopic Features of Botryoid Rhabdomyosarcoma (RMS): The individual polypoid areas are relatively hypocellular and have abundant myxoid stroma creating a resemblance to myxoma. According to the International Classification of Rhabdomyosarcoma, the defining feature of botryoid RMS is the presence of a cambium layer. It is a subepithelial condensed layer of tumor cells that is separated from the overlying epithelium by loose myxoid stroma. Image courtesy of: Dr. Miguel Reyes-Mugica, Chief of Pediatric Pathology, University of Pittsburgh, PA, USA; used with permission.