Dense pattern of embryonal rhabdomyosarcoma, a lesion easily confused with alveolar rhabdomyosarcoma: A report from the soft tissue sarcoma committee of the children's oncology group

Erin R. Rudzinski, Lisa A. Teot, James R. Anderson, Julie Moore, Julia A. Bridge, Frederic G. Barr, Julie M. Gastier-Foster, Stephen X. Skapek, Douglas S. Hawkins, David M. Parham

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Objectives: To examine whether the frequency of fusion-negative alveolar rhabdomyosarcoma (ARMSn) increased coincident with changes in the definition of alveolar histology. Methods: We re-reviewed alveolar rhabdomyosarcoma (ARMS) in the Children's Oncology Group study D9803, comparing histopathology with fusion status. Results: Our review of 255 original ARMS cases (compared with a control group of 38 embryonal rhabdomyosarcomas [ERMS] cases) revealed that many had an ARMS-like densely cellular pattern with cytologic features and myogenin expression more typical of ERMS. Following re-review, 84 (33%) cases of original ARMS were rediagnosed as ERMS. All reclassified ERMS, including dense ERMS, were fusion negative, whereas 82% of confirmed ARMS cases were fusion positive. Total ARMS diagnoses returned to historic rates of 25% to 30% of all rhabdomyosarcomas, and ARMSn decreased from 37% to 18% of ARMS cases. The outcome of reclassified ERMS was similar to confirmed ERMS. Conclusions: To address the role of fusion status in risk stratification, pathologists should include both a histologic diagnosis and an evaluation of fusion status for all new ARMS diagnoses.

Original languageEnglish (US)
Pages (from-to)82-90
Number of pages9
JournalAmerican journal of clinical pathology
Volume140
Issue number1
DOIs
StatePublished - Jul 1 2013

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Keywords

  • Alveolar rhabdomyosarcoma
  • Embryonal rhabdomyosarcoma
  • Histologic classification
  • Myogenin
  • Rhabdomyosarcoma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this

Rudzinski, E. R., Teot, L. A., Anderson, J. R., Moore, J., Bridge, J. A., Barr, F. G., Gastier-Foster, J. M., Skapek, S. X., Hawkins, D. S., & Parham, D. M. (2013). Dense pattern of embryonal rhabdomyosarcoma, a lesion easily confused with alveolar rhabdomyosarcoma: A report from the soft tissue sarcoma committee of the children's oncology group. American journal of clinical pathology, 140(1), 82-90. https://doi.org/10.1309/AJCPA1WN7ARPCMKQ