Breast
Fibroepithelial tumors
Fibroadenomatoid change
Author: Melissa Alexander, M.D., Ph.D.
Board of reviewers: Anna Biernacka, M.D., Ph.D.
Deputy Editor-in-Chief: Gary Tozbikian, M.D.
Last author update: 26 August 2024
Last staff update: 26 August 2024
Copyright: 2002-2025, PathologyOutlines.com, Inc.
PubMed Search: Fibroadenomatous / fibroadenomatoid change
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Alexander M. Fibroadenomatoid change. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastfibroadenomatoidchange.html. Accessed January 19th, 2025.
Definition / general
- Benign, often incidental finding in a background of fibrocystic changes
- Lesion with features resembling a fibroadenoma but lacking sharp circumscription
Essential features
- Proliferation of intralobular stroma with the formation of stromal nodularity that often appears to blend in with the surrounding breast tissue
- Morphologically reminiscent of a fibroadenoma but not forming a well circumscribed mass
- May represent an incipient fibroadenoma
- Often multifocal and surrounded by fibrocystic changes
Terminology
- Also known as fibroadenomatous change, fibroadenomatoid hyperplasia, fibroadenomatoid mastopathy, fibroadenomatosis, sclerosing lobular hyperplasia
- Less frequently referred to as mixed lesion, reflecting the common association of fibroadenomatoid change and fibrocystic changes
ICD coding
- ICD-10: N60.2 - fibroadenosis of breast
Epidemiology
- F > M
- Mean age: 28 - 34 years
- Represents 5 - 7% of nonneoplastic surgical biopsies in one study; 8% of nonneoplastic breast diagnoses in another
- Identified in 11.5% of excisions for fibrocystic changes or fibroadenoma in one study
- Identified in 16.2% of female to male (FTM) gender affirmation surgical cases in one study
- References: AJR Am J Roentgenol 1998;171:1331, Am J Epidemiol 1978;108:112, Hum Pathol 1984;15:336, Histopathology 2017;71:859, Pathology 1987;19:393
Sites
- Most common site is the upper outer quadrant of the breast (Hum Pathol 1984;15:336)
Pathophysiology
- Proliferation of intralobular stroma
- May represent a stage in the evolution of a fibroadenoma, produced by the coalescence of fibroadenomatoid nodules
- Reference: Hum Pathol 1984;15:336
Etiology
- Unknown; possibly due to or influenced by reproductive hormones, similar to fibroadenoma
Clinical features
- May be detected by imaging modalities (see Radiology description below) as a palpable mass or incidentally in breast tissue sampled for a different lesion
Diagnosis
- Breast imaging modalities with core biopsy (stereotactic, ultrasound or MRI guided) or surgery followed by histologic examination of resected tissue
- References: AJR Am J Roentgenol 1995;165:291, AJR Am J Roentgenol 1998;171:1331
Radiology description
- Hypoechoic mass
- Asymmetric increased density
- Suspicious granular clustered microcalcifications (more frequent in women > 50 years old)
- No suspicious radiographic findings in patient with palpable mass
- Complex cystic lesion
- Imaging findings in one study of fibroadenomatoid hyperplasia showed that
- 53% were well defined masses
- 33% had normal mammographic findings
- 13% had an asymmetric density
- 1% with mammographic calcifications
- References: AJR Am J Roentgenol 1995;165:291, AJR Am J Roentgenol 1998;171:1331, Hum Pathol 1984;15:336, J Ultrasound Med 2022;41:2071
Radiology images
Images hosted on other servers:
Well circumscribed nodule
Suspicious granular microcalcifications
Prognostic factors
- Widely considered to have no increased risk of malignancy
- Single study reported co-occurrence of fibroadenomatoid change and HER2 negative invasive breast carcinoma (PLoS One 2015;10:e0129500)
Case reports
- 12 year old girl with a 3 month history of enlarging right breast mass (Cytojournal 2006;3:8)
- 14 year old girl with a 3 month history of painless enlarging right breast lump (Acta Cytol 2001;45:765)
- 24 year old woman with a 7 cm mass (Gynecol Obstet Invest 2014;77:134)
- 69 year old man with heart failure treated with digoxin and spironolactone presented with bilateral gynecomastia (Am J Surg Pathol 1990;14:774)
Treatment
- No treatment required
Gross description
- Lesion appears dense and poorly circumscribed on cut section
- Difficult to distinguish from fibrocystic changes by gross examination
- Reference: Malays J Pathol 1991;13:101
Microscopic (histologic) description
- Proliferation of intralobular stroma containing epithelial elements, sometimes closely resembling a microfibroadenoma or microfibroadenomata
- Stroma may appear loose and cellular or dense and hyalinized
- Often multifocal in a background of fibrocystic changes, including cysts and adenosis
- Periphery may appear to blend into the surrounding breast tissue
- References: Hum Pathol 1984;15:336, Pathology 1987;19:393, Malays J Pathol 1991;13:101, AJR Am J Roentgenol 1998;171:1331, Schnitt: Biopsy Interpretation of the Breast, 3rd Edition, 2017
Microscopic (histologic) images
Contributed by Melissa Alexander, M.D., Ph.D.
Edges blend with surrounding tissue
Vague stromal nodularity
Poorly circumscribed
Background fibrocystic change
Multiple nodules
Multiple nodules
Loose versus dense hyalinized stroma
Dense stroma
Loose versus dense nodules
Loose stroma, compressed glands
Fibroadenomatoid nodule, compressed glands
Cytology description
- Elements similar to fibroadenoma, including stromal fragments; however, lacking other elements of fibroadenoma, including branching antler horn epithelial clusters (Cytojournal 2006;3:8, Acta Cytol 2001;45:765)
Sample pathology report
- Breast, right, core biopsy:
- Fibroadenomatoid change associated with calcifications (see comment)
- Comment: Correlation with specimen radiograph was performed.
Differential diagnosis
- Fibroadenoma:
- Well circumscribed mass comprised of stromal and epithelial components sharply demarcated from the surrounding breast parenchyma
- Hyaline fibrous involution of breast lobules (Mod Pathol 2019;32:1263):
- Symmetrical process characterized by terminal duct lobular units with atrophic epithelium and associated deposition of basal lamina-like hyaline material
- Higher frequency in patients with germline BRCA mutation
Additional references
Board review style question #1
A poorly circumscribed nodular focus was identified in a breast needle core biopsy, shown in the image above. Which of the following is the best diagnosis for this histologic finding?
- Apocrine metaplasia
- Columnar cell change
- Duct ectasia
- Fibroadenomatoid change
- Microcalcifications
Board review style answer #1
D. Fibroadenomatoid change. Proliferation of fibrous interlobular stroma with indistinct borders in a background of fibrocystic change defines this as fibroadenomatoid change. Answer A is incorrect because apocrine metaplasia would affect the cuboidal epithelium of the lobule. Answer C is incorrect because duct ectasia would affect the walls of the duct rather than the intralobular stroma. Answer B is incorrect because columnar cell change would show changes in the cells lining the lobules. Answer E is incorrect because no microcalcifications are seen here.
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Reference: Fibroadenomatoid change
Board review style question #2
Which of the following is true regarding fibroadenomatoid change?
- Arises from interlobular stroma
- Is considered a precursor lesion to invasive carcinoma
- Often presents in a background of fibrocystic changes
- Sharply circumscribed lesion on cut section
- Treatment is surgical excision
Board review style answer #2
C. Often presents in a background of fibrocystic changes. By definition, fibroadenomatoid change is an incidental finding in a background of fibrocystic change. Answer A is incorrect because fibroadenomatoid change is a proliferation of intralobular, rather than interlobular, stroma. Answer B is incorrect because while fibroadenomatoid change may represent an early stage of fibroadenoma, it is not a precursor to invasive carcinoma. Answer D is incorrect because fibroadenomatoid change is characterized by indistinct borders. Answer E is incorrect because no treatment is required.
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Reference: Fibroadenomatoid change
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