Fibroepithelial tumor

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Author: Mikael Häggström [note 1]

Gross examination

As per:

or mastectomy.

Microscopic evaluation


Characteristics of fibroepithelial tumor

Biplastic, having proliferation of both stromal and epithelial components,[note 2] arranged into either a pericanalicular pattern (stromal proliferation around epithelial structures), or an intracanalicular pattern (stromal proliferation compressing the epithelial structures into clefts).

Characteristics of fibroadenoma

Fibroadenomas characteristically display hypovascular stroma compared to malignant tumors.[1][2][3] Furthermore, the epithelial proliferation appears in a single terminal ductal unit and has duct-like spaces surrounded by a fibroblastic stroma. The basement membrane is intact.[4]

Characteristics of phyllodes tumor

Benign phyllodes tumor

In contrast to fibroadenomas, phyllodes tumors display a leaf-like architecture, and an increased stromal cellularity.[5] In needle biopsy specimens, phyllodes tumors can be diagnosed in a fibroepithelial tumor if there is prominent mitotic activity of ≥3 per 10 high power fields, or the finding of 3 or more of the following characteristic histologic features:[5]

  • Stromal overgrowth
  • Fat infiltration
  • Stromal fragmentation
  • Subepithelial stromal condensation
  • Stromal nuclear pleomorphism

Further workup

After diagnosing a fibroepithelial tumor, still exclude another type of breast cancer, which may arise within it:[6]

Breast cancer types

Breast cancer types, with relative incidences and prognoses.
Cancer type Histopathology Image
Invasive ductal carcinoma (IDC) Carcinomatous cells are seen below the basement membrane of lactiferous ducts. Otherwise, there are no specific histologic characteristics, essentially making it a diagnosis of exclusion.[7] Invasive ductal carcinoma, with occasional entrapped normal ducts.jpg
Ductal carcinoma in situ (DCIS) Malignant epithelial cells confined to the ductal system of the breast, without invasion through the basement membrane.[8] DCIS - Intraductal carcinoma of the breast.jpg
Invasive lobular carcinoma (ILC) The "classic" pattern is round or ovoid cells with little cytoplasm in a single-file infiltrating pattern, sometimes concentrically giving a targetoid pattern. Classic Invasive Lobular Carcinoma of the Breast (6813147194).jpg
Lobular carcinoma in situ (LCIS)
  • Monomorphic, loosely cohesive, slightly enlarged and evenly spaced cells that fill acini.[9]

Cells have indistinct cell borders, pale cytoplasm, and uniform small nuclei with evenly distributed chromatin and inconspicuous nucleoli.[9]

Histopathology of lobular carcinoma in situ.jpg
Mucinous carcinoma Extracellular mucin areas around tumor cells. Histopathology of mucinous invasive ductal carcinoma of the breast.jpg
Medullary carcinoma Seemingly fused tumor cells (syncytial pattern), and a prominent lymphoid infiltrate. Histopathology of medullary breast carcinoma.jpg

Microscopic report

If, even after consultation, it is not clear whether a tumor is a fibroadenoma or phyllodes tumor, then it can be reported as a cellular fibroepithelial lesion or a fibroepithelial neoplasm.

A phyllodes tumor warrants a comment whether margins are positive or negative for tumor, whereas fibroadenoma does not need such comment.

Example report of fibroadenoma:

Right breast, lumpectomy:

Negative for atypia or malignancy.


  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.
  2. The proliferation of two histological components is called "biplasia", from Latin bis (“twice”) and -plasia (“formation”), or "biphasic proliferation" (although the latter may refer to proliferation that has two chronological phases).

Main page


  1. Tavassoli, F.A., ed (2003). World Health Organization Classification of Tumours: Pathology & Genetics: Tumours of the breast and female genital organs . Lyon: IARC Press. ISBN 978-92-832-2412-9. 
  2. Jaya Ruth Asirvatham, M.B.B.S., Carlos C. Diez Freire, M.D., Cansu Karakas, M.D., Belinda Lategan, M.D., Nat Pernick, M.D., Emily S. Reisenbichler, M.D., Monika Roychowdhury, M.D., Mary Ann Gimenez Sanders, M.D, Ph.D., Gary Tozbikian, M.D., Hind Warzecha, M.D. Senior Authors: Julie M. Jorns, M.D., Shahla Masood. Breast nonmalignant, Fibroepithelial neoplasms, Fibroadenoma. Retrieved on 2019-11-04. Revised: 31 October 2019
  3. Rosen, PP. (2009). Rosen's Breast Pathology (3rd ed.). ISBN 978-0-7817-7137-5. 
  4. . Fibroadenoma of the breast.
  5. 5.0 5.1 Gary Tozbikian, M.D.. Breast - Fibroepithelial tumors - Fibroadenoma. Last author update: 19 July 2021. Last staff update: 22 July 2021
  6. Richard L Kempson MD, Robert V Rouse MD. Fibroadenoma of the Breast. Stanford University School of Medicine. May 27, 2006
  7. Peter Abdelmessieh. Breast Cancer Histology. Medscape. Retrieved on 2019-10-04. Updated: May 24, 2018
  8. Siziopikou, Kalliopi P. (2013). "Ductal Carcinoma In Situ of the Breast: Current Concepts and Future Directions ". Archives of Pathology & Laboratory Medicine 137 (4): 462–466. doi:10.5858/arpa.2012-0078-RA. ISSN 0003-9985. 
  9. 9.0 9.1 Sucheta Srivastava. Breast - Noninvasive lobular neoplasia - LCIS classic. Topic Completed: 1 September 2017. Minor changes: 21 June 2020

Image sources