Breast
Other carcinoma subtypes, not WHO classified
BRCA1 carcinoma


Topic Completed: 23 January 2020

Minor changes: 7 December 2020

Copyright: 2018-2021, PathologyOutlines.com, Inc.

PubMed search: BRCA1 associated [title] carcinoma breast

Shoko Vos, M.D., Ph.D.
Paul J. van Diest, M.D., Ph.D.
Page views in 2020: 1,555
Page views in 2021 to date: 63
Cite this page: Vos S, van Diest PJ. BRCA1 carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastmalignantbrca1.html. Accessed January 17th, 2021.
Definition / general
  • Breast cancer arising in patients with an underlying BRCA1 germline mutation
  • Tumor suppressor gene located on chromosome 17q21 (Science 1990;250:1684)
Essential features
Terminology
  • Also known as BRCA1 related breast cancer or BRCA1 germline mutation related breast cancer
  • BRCA1 associated breast cancer is not part of the WHO classification of breast tumors
ICD coding
  • No specific ICD-10 code; classification based on factors other than BRCA1 status
  • ICD-11: 2C65 - hereditary breast and ovarian cancer syndrome
Epidemiology
Pathophysiology
Etiology
  • Breast cancer arising in patients with an underlying BRCA1 germline mutation
Clinical features
Prognostic factors
Case reports
Treatment
Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Gary Tozbikian, M.D.

BRCA1 mutation associated breast carcinoma

Molecular / cytogenetics description
  • Tumor testing
  • Germline testing
    • High risk patients with breast cancer that meet criteria according to consensus guidelines (e.g. National Comprehensive Cancer Network [NCCN]) qualify for germline genetic testing; however, the American Society of Breast Surgeons recommends that genetic testing be available to all patients with newly diagnosed with breast cancer (Ann Surg Oncol 2019;26:3025)
    • BRCA1 germline mutation can also be detected by DNA sequencing analysis of breast tumors (J Mol Diagn 2018;20:600)
Molecular / cytogenetics images

Images hosted on other servers:

Large deletion

Pedigree

Splice variant

Sample pathology report
  • Right mastectomy:
    • Poorly differentiated invasive ductal breast carcinoma (see comment)
    • Sentinel nodes: no metastases / malignancy
    • Comment: Considering the age of the patient and the histology, a hereditary breast carcinoma should be considered.
    • Micro description: Sections show an atypical proliferation of irregular glands, solid groups and strands, composed of polymorphic cells with large, vesicular nuclei with prominent nucleoli and little cytoplasm. Mitotic count is 10 mitoses/10 HPF. Abundant peritumoral lymphocytes are seen. No signs of lymphovascular invasion. Microscopic diameter 2.0 cm. Bloom and Richardson grade 3 (tubule formation score: 3; nuclear size: score 3; mitotic count: score 2). ER negative (0%). PR negative (0%). HER2 negative (score 0). Foci of ductal carcinoma in situ were present around the tumor.
    • Sentinel nodes: 2 reactive lymph nodes. No signs of malignancy.
Differential diagnosis
Board review style question #1
Which statement about BRCA1 associated breast cancer is true?



  1. Frequently negative for CK5 / 6 expression
  2. Histology is often high grade lobular
  3. IHC often shows a triple negative tumor
  4. Has a low Ki67 labeling index
Board review style answer #1
C. IHC often shows a triple negative tumor

Comment here

Reference: BRCA1 associated breast carcinoma
Board review style answer #2
Which feature is associated with BRCA1 associated breast cancer?

  1. Ashkenazi Jewish heritage
  2. Diagnosis at age 50+ years
  3. Prominent neutrophilic infiltration
  4. BRCA1 somatic but not germline mutation
Board review style answer #2
A. Ashkenazi Jewish heritage

Comment here

Reference: BRCA1 associated breast carcinoma
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