Fibroadenoma

Breast Tumours (WHO Classification, 5th ed.)

Primary Author(s)*

H. Evin Gulbahce, MD and Katherine Geiersbach, MD

WHO Classification of Disease

Structure	Disease
Book	Breast Tumours (5th ed.)
Category	Fibroepithelial tumours and hamartomas of the breast
Family	Fibroepithelial tumours and hamartomas of the breast: Introduction
Type	Fibroadenoma
Subtype(s)	N/A

WHO Essential and Desirable Genetic Diagnostic Criteria

WHO Essential Criteria (Genetics)*
WHO Desirable Criteria (Genetics)*
Other Classification

*Note: These are only the genetic/genomic criteria. Additional diagnostic criteria can be found in the WHO Classification of Tumours.

Related Terminology

Acceptable
Not Recommended

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

Individual Region Genomic Gain/Loss/LOH

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

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)

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
MED12		Oncogene	Common	D		G44 hotspot mutations
TERT		Oncogene	Recurrent			Associated with juvenile fibroadenoma
RARA		Oncogene	Recurrent			Frequently co-mutated with MED12
EGFR		Oncogene	Rare
TP53		Tumor Suppressor Gene	Common			Associated with juvenile fibroadenoma and stromal PASH-like changes
PIK3CA		Oncogene	Rare
KMT2D		Tumor Suppressor Gene	Recurrent
NF1		Tumor Suppressor Gene	Rare
SETD2		Other	Common	D		Associated with juvenile fibroadenoma and PASH-like changes
FLNA		Oncogene	Common	D		Associated with juvenile fibroadenoma

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

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Genes and Main Pathways Involved

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Gene; Genetic Alteration	Pathway	Pathophysiologic Outcome

Links

https://www.pathologyoutlines.com/topic/breastfibroadenoma.html

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: “Fibroadenoma”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 05/1/2025, https://ccga.io/index.php/BRST5:Fibroadenoma.