Breast - nonmalignant
Benign tumors / changes
Cellular fibroadenoma of breast

Topic Completed: 1 March 2017

Revised: 16 January 2019

Copyright: (c) 2002-2019,, Inc.

PubMed Search: Cellular (juvenile) fibroadenoma of breast
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Cite this page: Roychowdhury M, Nassar H Cellular fibroadenoma of breast. website. Accessed February 19th, 2019.
Definition / general
  • Resembles fibroadenoma with pericanalicular pattern but more cellular
Essential features
  • Fibroadenoma (stromal and epithelial process) with uniform epithelial and stromal hypercellularity but lacking leaf-like pattern of phyllodes tumor
  • No atypical features, i.e. no periductal stromal condensation, no cytologic atypia, no mitotic figures > 3/10 HPF
  • Excision is curative
  • Also called juvenile fibroadenoma
  • Giant fibroadenoma: terminology used inconsistently; refers to size, often children but not a distinct histopathologic entity
  • Usually black females, median age 15 years (range 10 - 39 years)
Clinical features
  • Grows rapidly but benign behavior
  • Often massive size
  • Either solitary or multiple / successive lesions; recurrences usually cease in 20's
  • Not associated with subsequent carcinoma
Case reports
Gross description
  • Yellowish tan, softer than classic fibroadenoma
Gross images

Images hosted on other servers:

Well circumscribed
lobulated mass

Microscopic (histologic) description
  • Resembles fibroadenoma with pericanalicular pattern, may be mixed with intracanalicular pattern
    • Uniformly hypercellular stroma, no atypical features; i.e. no periductal increase in cellularity, no stromal overgrowth, no cytologic atypia, no mitotic figures > 3/10 HPF
    • Frequently epithelial as well as myoepithelial hyperplasia
  • Stromal and epithelial balance is not altered; lacks leaf-like growth pattern
  • Epithelium may have tufted pattern or hyperplasia characteristic of gynecomastia; may have epithelial atypia (Am J Surg Pathol 1987;11:184)
  • No increase in periductal cellularity that is seen in phyllodes tumors
Microscopic (histologic) images

Contributed by Debra L. Zynger, M.D.

Cellular fibroadenoma

Images hosted on other servers:

Juvenile fibroadenoma

Juvenile fibroadenoma - stromal and epithelial hyperplasia

Mitosis - infrequent finding

Fibroepithelial tumor with florid intraductal epithelial hyperplasia

(Myo)fibroblastic stroma, duct with columnar epithelium

Positive calponin


Cytology images

Images hosted on other servers:

Monolayered sheets of ductal cells

Monolayered sheets of epithelial cells

Differential diagnosis
  • Hamartoma: more abundant adipose tissue; epithelial component is more disorganized
  • Phyllodes tumor: prominent stromal overgrowth, intracanalicular growth pattern, periductal concentration of cells, variable atypia and mitotic figures
Board review question #1
Which feature supports a diagnosis of phyllodes tumor over cellular fibroadenoma?

  1. Epithelial tufting or hyperplasia
  2. Pericanalicular pattern
  3. Periductal condensation of stromal cells
  4. Young patient
Board review answer #1
C. Periductal condensation of stromal cells; features supporting a diagnosis of phyllodes tumor over cellular fibroadenoma are an older patient, intracanalicular pattern with leaf like formations, periductal condensation of stromal cells, cytologic atypia and increased mitotic activity