Botryoid Rhabdomyosarcoma : Introduction

Comments:
Botryoid rhabdomyosarcoma accounts for 6% of all rhabdomyosarcomas (RMS). It has a characteristic polypoid, grape-like gross appearance. In the 4th Edition (2013) of the WHO Classification of the Tumours of Soft Tissue and Bone, botryoid type is included in embryonal RMS instead of being recognized as an independent entity.

Note: Despite earlier definitions, the International Classification of Rhabdomyosarcoma does not required grape-like gross appearance for the diagnosis of botryoid RMS. However, a cambium layer must be present. It is a subepithelial condensed layer of tumor cells that is separated from the overlying epithelium by loose myxoid stroma.

Image courtesy of Dr. Jean-Christophe Fournet, Paris, France; humpath.com; Used with permission