Breast

Other carcinoma subtypes, WHO classified

Adenoid cystic

Editor-in-Chief: Debra L. Zynger, M.D.

Topic Completed: 30 December 2019

Minor changes: 23 December 2021

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Table of Contents

Cite this page: Tozbikian G. Adenoid cystic. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastmalignantadenoidcystic.html. Accessed January 19th, 2022.

Definition / general

Histologically similar to salivary gland counterpart
Triple negative and basal-like subtype of mammary carcinoma with excellent long term survival

Epidemiology

Rare, 0.1% of breast carcinomas (Am J Surg 2002;183:646)
Mean age 64 years, range 25 - 80 years (Breast Cancer Res 2010;12:R54)
May be associated with microglandular adenosis (Am J Surg Pathol 2003;27:1052)

Diagnosis

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.

Mammogram

Images hosted on other servers:

MRI

Prognostic factors

Low rates of recurrence and better long term outcome compared with ductal NOS type (Breast 2012;21:124, Breast Cancer Res Treat 2004;87:225, Breast Cancer Res 2010;12:R54, J Clin Pathol 2010;63:220)
High rates of positive margins (Am J Clin Oncol 2010;33:28)
Axillary nodal metastases are rare, more frequently seen in solid variant (Am J Surg Pathol 2002;26:413)
Treatment is excision with clear margins, possibly radiation, axillary dissection may not be necessary (J Surg Oncol 2010;102:342, Breast 2017;31:214)

Case reports

21 year old man with left nipple swelling (Breast J 2019 Sep 6 [Epub ahead of print])
56 year old woman with a breast mass (Case Rep Oncol 2019;12:698)
63 year old woman with a breast mass (J Surg Case Rep 2019;2019:rjy355)
65 year old woman with breast mass, metastases to lung, kidney and brain (J Med Case Rep 2017;11:303)
69 year old woman with a breast mass (Ann Med Surg (Lond) 2019;43:1)
71 year old woman with a breast mass (Int J Surg Case Rep 2018;42:196)
85 year old woman with a breast mass (J Med Invest 2018;65:289)

Gross description

1 - 3 cm, well circumscribed, firm
May have cystic cut surface

Microscopic (histologic) description

Dual population of cells (Arch Pathol Lab Med 1986;110:1045):
1. Luminal / ductal epithelial cells with variable glandular / squamous / sebaceous differentiation
2. Myoepithelial / basaloid cells
Cribriform, solid, tubular or trabecular architectural patterns
2 types of lumens that are lined by 2 cell types:
1. True glandular lumina lined by luminal / ductal epithelial cells (low molecular weight cytokeratin+, CK7+)
2. 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+)
Solid variant: prominent basaloid features with more aggressive clinical course (Am J Surg Pathol 2002;26:413, APMIS 1999;107:762, BMJ Case Rep 2011;2011:bcr0820114692)

Microscopic (histologic) images

Contributed by Gary Tozbikian, M.D.

Adenoid cystic carcinoma

Estrogen receptor

p40

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.

FNA

Images hosted on other servers:

Papanicolaou

Monomorphic tumor cells around mucoid material

Positive stains

Luminal / ductal epithelial cells:
Basaloid / myoepithelial type cells:
Secretions in true lumina:
- PAS+ diastase resistant
Cribriform spaces:
- Alcian blue (Am J Clin Pathol 2005;124:733)
Pseudolumen secretions:
- Laminin
- Collagen IV

Negative stains

Estrogen receptor, progesterone receptor (usually), HER2 (Mod Pathol 2005;18:1277)

Molecular / cytogenetics description

MYB-NFIB fusion gene (t(6;9)(q22-23;p23-24)) identified in the majority adenoid cystic carcinomas of breast, as well as in solid variant (J Pathol 2012;226:84, Proc Natl Acad Sci U S A 2009;106:18740, Hum Pathol 2014;45:2270)
Molecular profiling of adenoid cystic carcinomas assign them to the basal-like subtype but have lower genetic instability and copy number aberrations compared with metaplastic, medullary and basal-like no special type (NST) tumors (Breast Cancer Res Treat 2013;142:257, Histopathology 2013;62:543, J Pathol 2008;216:141)

Differential diagnosis

Collagenous spherulosis:
- Noninfiltrative proliferation of myoepithelial cells enclosing basement membrane material confined within preexisting ducts / lobules and lacking epithelial cell component
- Lacks dual cell population
- Calponin+, smooth muscle myosin heavy chain / SMMHC+, CD117 / KIT- (Mod Pathol 2006;19:1351)
Invasive cribriform carcinoma:
- Infiltrative glands lack circumscription by myoepithelial cells (myoepithelial cells limited to periphery of ducts involved by ductal carcinoma in situ component)
- Lacks dual cell population
- Estrogen receptor+, progesterone receptor+, CD117 / KIT-

Additional references

Am J Surg Pathol 1998;22:569, Hum Pathol 1987;18:1276, Mod Pathol 1996;9:215, Stanford University: Adenoid Cystic Carcinoma of the Breast [Accessed 20 December 2019]

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 below). Which statement is true regarding this tumor?

Frequently shows regional lymph node metastases
Represents ~5% of all mammary cancers
Triple negative for ER / PR / HER2 and has an aggressive clinical course
Recurrent t(12;15)(p13;q25) translocation resulting in ETV6-NTRK3 gene fusion is commonly seen
CD117 / KIT expression is present in the luminal / ductal epithelial cell component

Board review style answer #1

E. 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 choice D) 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?

CD117 / KIT positive, estrogen receptor positive
CD117 / KIT negative, estrogen receptor negative
MYB positive, estrogen receptor negative
MYB positive, HER2 positive
CD117 / KIT positive, HER2 positive

Board review style answer #2

C. 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