Resolving quandaries: basaloid adenoid cystic carcinoma or breast cylindroma? The role of massively parallel sequencing

Histopathology. 2016 Jan;68(2):262-71. doi: 10.1111/his.12735. Epub 2015 Jun 29.


Aims: The aims of this study were to perform a whole-exome sequencing analysis of a breast cylindroma and to investigate the role of molecular analyses in the differentiation between breast cylindroma, a benign tumour that displays MYB expression, and CYLD gene mutations, and its main differential diagnosis, the breast solid-basaloid adenoid cystic carcinoma, a malignant tumour that is characterized by the presence of the MYB-NFIB fusion gene and MYB overexpression.

Methods and results: A 66-year-old female underwent quadrantectomy after an irregular dense shadow was discovered in the right breast at the screening mammogram. Histologically, the tumour displayed features suggestive of a solid-basaloid variant of adenoid cystic carcinoma with a differential diagnosis of cylindroma. Fluorescence in situ hybridization, reverse transcription-polymerase chain reaction, immunohistochemistry and whole-exome sequencing revealed absence of the MYB-NFIB fusion gene, low levels of MYB protein expression and a clonal somatic CYLD splice site mutation associated with loss of heterozygosity of the wild-type allele.

Conclusions: The results of the histological, immunohistochemical and molecular analyses were consistent with a diagnosis of breast cylindroma, providing a proof-of-principle that the integration of histopathological and molecular approaches can help to differentiate between a low-malignant potential and a benign breast tumour of triple-negative phenotype.

Keywords: adenoid cystic carcinoma; breast cancer; cylindroma; fluorescence in-situ hybridization; massively parallel sequencing.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers, Tumor / genetics*
  • Biomarkers, Tumor / metabolism
  • Breast / pathology
  • Breast Neoplasms / diagnosis*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology
  • Breast Neoplasms / surgery
  • Carcinoma, Adenoid Cystic / diagnosis*
  • Carcinoma, Adenoid Cystic / genetics
  • Carcinoma, Adenoid Cystic / pathology
  • Carcinoma, Adenoid Cystic / surgery
  • Exome / genetics
  • Female
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Mastectomy, Segmental
  • Phenotype
  • Sequence Analysis, DNA


  • Biomarkers, Tumor

Associated data

  • GENBANK/SRP052995