Other invasive carcinoma subtypes, WHO classified

Adenoid cystic

Editorial Board Member: Kristen E. Muller, D.O.
Editor-in-Chief: Debra L. Zynger, M.D.
Gary Tozbikian, M.D.

Last author update: 16 May 2023
Last staff update: 16 May 2023

Copyright: 2002-2023,, Inc.

PubMed Search: Adenoid cystic carcinoma breast

Gary Tozbikian, M.D.
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Cite this page: Tozbikian G. Adenoid cystic. website. Accessed June 8th, 2023.
Definition / general
  • Histologically similar to salivary gland counterpart
  • Triple negative and basal-like subtype of mammary carcinoma with excellent long term survival
Essential features
  • Rare subtype of breast cancer, histomorphologically identical to salivary gland counterpart
  • Comprised of epithelial and myoepithelial cells arranged in solid, cribriform or tubular arrangements and associated basement membrane material
  • Associated with MYB::NFIB fusion
ICD coding
  • ICD-10: C50.91 - malignant neoplasm of breast of unspecified site, female
  • Mammogram or other imaging detects a mass
  • Diagnosis made by tissue biopsy or resection, often utilizing immunohistochemistry
Radiology images

Contributed by Mark R. Wick, M.D.


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Prognostic factors
Case reports
Gross description
Microscopic (histologic) description
  • Dual population of cells (Arch Pathol Lab Med 1986;110:1045):
    • Luminal / ductal epithelial cells with variable glandular / squamous / sebaceous differentiation
    • Myoepithelial / basaloid cells
  • Cribriform, solid, tubular or trabecular architectural patterns
  • 2 types of lumens that are lined by 2 cell types
    • True glandular lumina lined by luminal / ductal epithelial cells (low molecular weight cytokeratin+, CK7+)
    • Pseudolumens containing eosinophilic cylinders comprised of basement membrane material (laminin and collagen IV positive) lined by myoepithelial / basal type cells (p63 / p40+, smooth muscle myosin+, calponin+, high molecular weight cytokeratin+, S100+)
  • Histologic variants
Microscopic (histologic) images

Contributed by Gary Tozbikian, M.D.

Extensive cribriform architecture, infiltrative growth pattern

Dual population of basaloid and epithelioid cells

Estrogen receptor


CD117 / KIT

Cytology description
  • Clusters of epithelial cells oriented around solid spheres of basement membrane material
Cytology images

Contributed by Mark R. Wick, M.D.


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Monomorphic tumor cells around mucoid material

Positive stains
Molecular / cytogenetics description
Sample pathology report
  • Left breast, mass 10:00, ultrasound guided core needle biopsy:
    • Adenoid cystic carcinoma, 1.2 cm in greatest length (see comment)
    • Estrogen receptor: negative (0%, no intensity)
    • Progesterone receptor: negative (0%, no intensity)
    • HER2: negative (score 0)
    • Comment: Additional immunohistochemical stains show that the tumor is positive for CD117, MYB and p40 (in basaloid cells), supporting the diagnosis.
Differential diagnosis
Board review style question #1

A 55 year old woman undergoes an excision for a 3 cm breast mass (histologic image of the tumor is shown above). Which statement is true regarding this tumor?

  1. CD117 / KIT expression is present in the luminal / ductal epithelial cell component
  2. Frequently shows regional lymph node metastases
  3. Recurrent t(12;15)(p13;q25) translocation resulting in ETV6::NTRK3 gene fusion is commonly seen
  4. Represents ~5% of all mammary cancers
  5. Triple negative for ER / PR / HER2 and has an aggressive clinical course
Board review style answer #1
A. CD117 / KIT expression is present in the luminal / ductal epithelial cell component. The excision shows an adenoid cystic carcinoma, which is a rare subtype of mammary carcinoma representing < 1% of breast cancers. Despite triple negative status, these tumors generally show excellent long term survival. Similar to the salivary gland counterparts, adenoid cystic carcinomas of the breast are characterized by t(6;9)(q22-23;p23-24) translocation resulting in a MYB::NFIB fusion gene. The t(12;15)(p13;q25) translocation resulting in ETV6::NTRK3 gene fusion (answer C) is seen in secretory carcinoma of the breast. Consistent CD117 / KIT protein expression is observed in most adenoid cystic carcinomas of the breast; however, underlying KIT gene alterations have not been identified (Histopathology 2013;62:543).

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Reference: Adenoid cystic carcinoma
Board review style question #2
Which immunohistochemical stain finding is typically observed in adenoid cystic carcinoma of the breast?

  1. CD117 / KIT negative, estrogen receptor negative
  2. CD117 / KIT positive, estrogen receptor positive
  3. CD117 / KIT positive, HER2 positive
  4. MYB positive, estrogen receptor negative
  5. MYB positive, HER2 positive
Board review style answer #2
D. MYB positive, estrogen receptor negative. Adenoid cystic carcinoma of the breast is a biphasic tumor comprised of a ductal / epithelial cell and myoepithelial / basaloid cell components. The ductal / epithelial cells are immunoreactive for low molecular weight keratins such as CK7 and CK8/18. The myoepithelial / basaloid cell component is positive for high molecular weight keratins (CK5/6, CK14, CK17) and myoepithelial markers (p40 / p63, SMMS, calponin). Additionally, mammary adenoid cystic carcinomas generally express CD117 / KIT and MYB, and are triple negative for estrogen receptor, progesterone receptor and HER2.

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Reference: Adenoid cystic carcinoma
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