Simple bone cyst

Soft Tissue and Bone Tumours (Who Classification, 5th ed.)

Primary Author(s)*

Kathleen Schieffer, PhD, FACMG

WHO Classification of Disease

Structure	Disease
Book	Soft Tissue and Bone Tumours (5th ed.)
Category	Bone tumours
Family	Other mesenchymal tumours of bone
Type	Simple bone cyst
Subtype(s)	N/A

Related Terminology

Acceptable	Solitary bone cyst
Not Recommended	Unicameral bone cyst

Gene Rearrangements

Driver Gene	Fusion(s) and Common Partner Genes	Molecular Pathogenesis	Typical Chromosomal Alteration(s)	Prevalence -Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes
NFATC2	EWSR1, FUS	In-frame fusion that retains the N-terminal domain of EWSR1 or FUS and the DNA-binding domain of the transcription factor, NFATC2. It is predicted that the truncated NFATC2 protein, which has lost the regulatory domain as a result of the fusion, leads to constitutive activation of this transcription factor and downstream signaling. The breakpoints typically involve exon 6 of EWSR1 (NM_005243.4) or exon 6 of FUS (NM_004960.4) and exon 3 of NFATC2 (NM_012340.5).	t(16;20)(p11.2;q13) [FUS::NFATC2]	Recurrent*	D	No	Early cytogenetic analysis identified a t(16;20)(p11.2;q13) in a single simple bone cyst specimen. Molecular studies identified a recurrent fusion between either EWSR1 or FUS and NFATC2.

*Please note that limited studies have been performed from simple bone cysts and the prevalence requires additional study.

Individual Region Genomic Gain/Loss/LOH

No recurrent copy number findings are described. A single report of cytogenetic complexity have been described.

Chr #	Gain, Loss, Amp, LOH	Minimal Region Cytoband and/or Genomic Coordinates [Genome Build; Size]	Relevant Gene(s)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Characteristic Chromosomal or Other Global Mutational Patterns

None

Chromosomal Pattern	Molecular Pathogenesis	Prevalence - Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Gene Mutations (SNV/INDEL)

None

Gene	Genetic Alteration	Tumor Suppressor Gene, Oncogene, Other	Prevalence - Common >20%, Recurrent 5-20% or Rare <5% (Disease)	Diagnostic, Prognostic, and Therapeutic Significance - D, P, T	Established Clinical Significance Per Guidelines - Yes or No (Source)	Clinical Relevance Details/Other Notes

Note: A more extensive list of mutations can be found in cBioportal, COSMIC, and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

Epigenomic Alterations

None

Genes and Main Pathways Involved

None

Gene; Genetic Alteration	Pathway	Pathophysiologic Outcome

Genetic Diagnostic Testing Methods

1. Fusion testing
   • Targeted sequencing (such as RT-PCR or targeted next-generation sequencing (NGS) panels)
     • For targeted NGS panels, consider if the assay requires both gene partners to be included on the panel or if it is able to identify novel fusions as long as one of the partners is included on the panel
   • Whole transcriptome RNA-sequencing
     • Provides an unbiased approach to fusion calling

Familial Forms

Not applicable

Additional Information

Not applicable

Links

None

Notes

*Primary authors will typically be those that initially create and complete the content of a page.  If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the Associate Editor or other CCGA representative.  When pages have a major update, the new author will be acknowledged at the beginning of the page, and those who contributed previously will be acknowledged below as a prior author.

Prior Author(s): *Citation of this Page: “Simple bone cyst”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 10/21/2025, https://ccga.io/index.php/STBT5:Simple bone cyst.