Rhabdomyosarcoma: Updates on classification and the necessity of molecular testing beyond immunohistochemistry

Carina A Dehner; Erin R Rudzinski; Jessica L Davis

doi:10.1016/j.humpath.2023.12.004

Rhabdomyosarcoma: Updates on classification and the necessity of molecular testing beyond immunohistochemistry

Hum Pathol. 2023 Dec 21:S0046-8177(23)00251-4. doi: 10.1016/j.humpath.2023.12.004. Online ahead of print.

Authors

Carina A Dehner¹, Erin R Rudzinski², Jessica L Davis³

Affiliations

¹ Department of Pathology & Laboratory Medicine, Indiana University, Indianapolis, IN, USA.
² Department of Laboratories, Seattle Children's Hospital and Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, WA, USA.
³ Department of Pathology & Laboratory Medicine, Indiana University, Indianapolis, IN, USA. Electronic address: jld13@iu.edu.

PMID: 38135061
DOI: 10.1016/j.humpath.2023.12.004

Abstract

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents under the age of 20. The current World Health Organization (WHO) classification for soft tissue and bone tumors recognizes 4 distinct subtypes of RMS based on clinicopathological and molecular genetic features: embryonal, alveolar, spindle cell/sclerosing and pleomorphic subtypes. However, with the increased use of molecular techniques, the classification of rhabdomyosarcoma has been evolving rapidly. New subtypes such as osseus RMS harboring TFCP2/NCOA2 fusions or RMS arising in inflammatory rhabdomyoblastic tumor have been emerging within the last decade, adding to the complexity of diagnosing skeletal muscle tumors. This review article provides an overview of classically recognized distinctive subtypes as well as new, evolving subtypes and discusses important morphologic, immunophenotypic and molecular genetic features of each subtype including recommendations for a diagnostic approach of malignant skeletal muscle neoplasms.

Keywords: Alveolar; Embryonal; FOXO1; Rhabdomyosarcoma; Sarcoma; Spindle cell/sclerosing.

Publication types

Review