Malignant Ectomesenchymoma: Series Analysis of a Histologically and Genetically Heterogeneous Tumor

Brannan B. Griffin, Pauline M. Chou, David George, Lawrence J. Jennings, Nicoleta C. Arva*

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Aims. Malignant ectomesenchymoma is a rare pediatric neoplasm with dual mesenchymal and neuroectodermal elements. Mesenchymal component is usually rhabdomyosarcoma, particularly embryonal subtype, whereas neuroectodermal derivatives are frequently a neuroblastic tumor. Ectomesenchymoma manifests in various sites given the wide migration of neural crest cells during development, though the pelvis/perineum is most often involved. Moreover, no unique unifying molecular abnormality has been determined. Methods. We conducted a retrospective study to analyze the spectrum of ectomesenchymal tumors encountered in our pediatric population. Six patients were identified and data pertaining to patients’ demographic, tumor size and site, histologic components with immunophenotypic profile, molecular alterations, treatment, and outcome were collected. Results. Mesenchymal elements, represented by rhabdomyosarcoma in all instances, were the dominant component in the majority of cases (5/6). Embryonal and alveolar morphology had similar distribution (3/6) and all patients with alveolar subtype harbored the characteristic translocations of this entity. The neuroectodermal component was most often a neuroblastic-like neoplasm (4/6); however, 2/6 cases demonstrated primitive neuroectodermal tumor-like morphology. No unifying alterations were found on molecular studies. Conclusions. Our analysis extends the histologic and molecular spectrum of these tumors and highlights their heterogeneity. The percentage of cases with alveolar rhabdomyosarcoma or primitive neuroectodermal-like tumor components suggests that these types of elements might be underreported. This study is also the first to demonstrate FOXO1 gene rearrangements in malignant ectomesenchymoma with alveolar rhabdomyosarcoma subtype.

Original languageEnglish (US)
Pages (from-to)200-212
Number of pages13
JournalInternational Journal of Surgical Pathology
Volume26
Issue number3
DOIs
StatePublished - May 1 2018

Fingerprint

Alveolar Rhabdomyosarcoma
Primitive Neuroectodermal Tumors
Neoplasms
Embryonal Rhabdomyosarcoma
Pediatrics
Perineum
Rhabdomyosarcoma
Gene Rearrangement
Neural Crest
Pelvis
Spectrum Analysis
Retrospective Studies
Demography
Population

Keywords

  • ectomesenchymoma
  • neural crest
  • primitive neuroectodermal tumor
  • rhabdomyosarcoma

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

Cite this

@article{4a6c73e89fa540f89d7d3b97cec353e3,
title = "Malignant Ectomesenchymoma: Series Analysis of a Histologically and Genetically Heterogeneous Tumor",
abstract = "Aims. Malignant ectomesenchymoma is a rare pediatric neoplasm with dual mesenchymal and neuroectodermal elements. Mesenchymal component is usually rhabdomyosarcoma, particularly embryonal subtype, whereas neuroectodermal derivatives are frequently a neuroblastic tumor. Ectomesenchymoma manifests in various sites given the wide migration of neural crest cells during development, though the pelvis/perineum is most often involved. Moreover, no unique unifying molecular abnormality has been determined. Methods. We conducted a retrospective study to analyze the spectrum of ectomesenchymal tumors encountered in our pediatric population. Six patients were identified and data pertaining to patients’ demographic, tumor size and site, histologic components with immunophenotypic profile, molecular alterations, treatment, and outcome were collected. Results. Mesenchymal elements, represented by rhabdomyosarcoma in all instances, were the dominant component in the majority of cases (5/6). Embryonal and alveolar morphology had similar distribution (3/6) and all patients with alveolar subtype harbored the characteristic translocations of this entity. The neuroectodermal component was most often a neuroblastic-like neoplasm (4/6); however, 2/6 cases demonstrated primitive neuroectodermal tumor-like morphology. No unifying alterations were found on molecular studies. Conclusions. Our analysis extends the histologic and molecular spectrum of these tumors and highlights their heterogeneity. The percentage of cases with alveolar rhabdomyosarcoma or primitive neuroectodermal-like tumor components suggests that these types of elements might be underreported. This study is also the first to demonstrate FOXO1 gene rearrangements in malignant ectomesenchymoma with alveolar rhabdomyosarcoma subtype.",
keywords = "ectomesenchymoma, neural crest, primitive neuroectodermal tumor, rhabdomyosarcoma",
author = "Griffin, {Brannan B.} and Chou, {Pauline M.} and David George and Jennings, {Lawrence J.} and Arva, {Nicoleta C.}",
year = "2018",
month = "5",
day = "1",
doi = "10.1177/1066896917734915",
language = "English (US)",
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pages = "200--212",
journal = "International Journal of Surgical Pathology",
issn = "1066-8969",
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TY - JOUR

T1 - Malignant Ectomesenchymoma

T2 - Series Analysis of a Histologically and Genetically Heterogeneous Tumor

AU - Griffin, Brannan B.

AU - Chou, Pauline M.

AU - George, David

AU - Jennings, Lawrence J.

AU - Arva, Nicoleta C.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - Aims. Malignant ectomesenchymoma is a rare pediatric neoplasm with dual mesenchymal and neuroectodermal elements. Mesenchymal component is usually rhabdomyosarcoma, particularly embryonal subtype, whereas neuroectodermal derivatives are frequently a neuroblastic tumor. Ectomesenchymoma manifests in various sites given the wide migration of neural crest cells during development, though the pelvis/perineum is most often involved. Moreover, no unique unifying molecular abnormality has been determined. Methods. We conducted a retrospective study to analyze the spectrum of ectomesenchymal tumors encountered in our pediatric population. Six patients were identified and data pertaining to patients’ demographic, tumor size and site, histologic components with immunophenotypic profile, molecular alterations, treatment, and outcome were collected. Results. Mesenchymal elements, represented by rhabdomyosarcoma in all instances, were the dominant component in the majority of cases (5/6). Embryonal and alveolar morphology had similar distribution (3/6) and all patients with alveolar subtype harbored the characteristic translocations of this entity. The neuroectodermal component was most often a neuroblastic-like neoplasm (4/6); however, 2/6 cases demonstrated primitive neuroectodermal tumor-like morphology. No unifying alterations were found on molecular studies. Conclusions. Our analysis extends the histologic and molecular spectrum of these tumors and highlights their heterogeneity. The percentage of cases with alveolar rhabdomyosarcoma or primitive neuroectodermal-like tumor components suggests that these types of elements might be underreported. This study is also the first to demonstrate FOXO1 gene rearrangements in malignant ectomesenchymoma with alveolar rhabdomyosarcoma subtype.

AB - Aims. Malignant ectomesenchymoma is a rare pediatric neoplasm with dual mesenchymal and neuroectodermal elements. Mesenchymal component is usually rhabdomyosarcoma, particularly embryonal subtype, whereas neuroectodermal derivatives are frequently a neuroblastic tumor. Ectomesenchymoma manifests in various sites given the wide migration of neural crest cells during development, though the pelvis/perineum is most often involved. Moreover, no unique unifying molecular abnormality has been determined. Methods. We conducted a retrospective study to analyze the spectrum of ectomesenchymal tumors encountered in our pediatric population. Six patients were identified and data pertaining to patients’ demographic, tumor size and site, histologic components with immunophenotypic profile, molecular alterations, treatment, and outcome were collected. Results. Mesenchymal elements, represented by rhabdomyosarcoma in all instances, were the dominant component in the majority of cases (5/6). Embryonal and alveolar morphology had similar distribution (3/6) and all patients with alveolar subtype harbored the characteristic translocations of this entity. The neuroectodermal component was most often a neuroblastic-like neoplasm (4/6); however, 2/6 cases demonstrated primitive neuroectodermal tumor-like morphology. No unifying alterations were found on molecular studies. Conclusions. Our analysis extends the histologic and molecular spectrum of these tumors and highlights their heterogeneity. The percentage of cases with alveolar rhabdomyosarcoma or primitive neuroectodermal-like tumor components suggests that these types of elements might be underreported. This study is also the first to demonstrate FOXO1 gene rearrangements in malignant ectomesenchymoma with alveolar rhabdomyosarcoma subtype.

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