RT Journal Article SR Electronic T1 Genetics and genomics of breast fibroadenomas JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 381 OP 387 DO 10.1136/jclinpath-2017-204838 VO 71 IS 5 A1 Benjamin Nathanael Loke A1 Nur Diyana Md Nasir A1 Aye Aye Thike A1 Jonathan Yu Han Lee A1 Cheok Soon Lee A1 Bin Tean Teh A1 Puay Hoon Tan YR 2018 UL http://jcp.bmj.com/content/71/5/381.abstract AB Fibroadenomas of the breast are benign fibroepithelial tumours most frequently encountered in women of reproductive age, although they may be diagnosed at any age. The fibroadenoma comprises a proliferation of both stromal and epithelial components. The mechanisms underlying fibroadenoma pathogenesis remain incompletely understood. In the clinical setting, distinguishing cellular fibroadenomas from benign phyllodes tumours is a common diagnostic challenge due to subjective histopathological criteria and interobserver differences. Recent sequencing studies have demonstrated the presence of highly recurrent mutations in fibroadenomas, and also delineated the genomic landscapes of fibroadenomas and the closely related phyllodes tumours, revealing differences at the gene level, which may be of potential adjunctive diagnostic use. The present article provides an overview of key studies uncovering genetic and genomic abnormalities in fibroadenomas, from initial karyotype reports revealing myriad cytogenetic aberrations to next-generation sequencing-based approaches that led to the discovery of highly recurrent MED12 mutations. A thorough understanding of these abnormalities is important to further elucidate the mechanisms by which fibroadenomas arise and to refine diagnostic assessment of this very common tumour.