Breast nonmalignant
Fibroepithelial neoplasms
Phyllodes tumor - benign

Topic Completed: 1 April 2010

Minor changes: 22 May 2020

Copyright: 2002-2019,, Inc.

PubMed Search:: Benign phyllodes tumor [title] breast

See also: Phyllodes - generalPhyllodes - borderlinePhyllodes - malignant

Hind Warzecha, M.D.
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Cite this page: Nassar H Phyllodes benign. website. Accessed May 31st, 2020.
Definition / general
  • Phyllodes features but no / rare mitotic figures, no atypia
  • Also called low grade because even histologically benign appearing tumors may have malignant behavior
Clinical features
  • Most (75%) phyllodes tumors are benign
  • May have benign adipose tissue as primary stromal component (lipophyllodes tumor, Arch Pathol Lab Med 1994;118:91)
  • May recur locally but only rare distant metastases
Radiology images

Contributed by Dr. Mark R. Wick:


Case reports
  • Excision with 1 - 2 cm margins (Mod Pathol 2001;14:185)
  • Breast preservation if possible, particular in young women
Gross description
  • Well circumscribed, firm, gray white cut surface with cleft-like spaces resembling a leaf
  • Variable cysts, hemorrhage, necrosis (more common in larger tumors)
Gross images

Contributed by Dr. Mark R. Wick:

Various images

Images hosted on other servers:

Large, well circumscribed tumors

Multiple, polypoid nodules

Well circumscribed with firm consistency

Necrosis, hemorrhage and cystic degeneration

Microscopic (histologic) description
  • Circumscribed pushing border, stromal hypercellularity (particularly next to epithelial elements) and benign glandular elements with intracanalicular pattern but ratio is balanced
  • Stroma resembles fibroblasts and myofibroblasts
  • Epithelial component has luminal epithelial cells resting on myoepithelial layer
  • May exhibit hyperplasia, squamous metaplasia
  • May have clusters of multinucleated giant cells (Arch Pathol Lab Med 1994;118:912)
  • Variable hemorrhage, necrosis, fat, bone, cartilage and skeletal muscle
  • 0 - 4 mitotic figures/10 HPF
  • No atypia
Microscopic (histologic) images

Contributed by Dr. Mark R. Wick:

Low grade

AFIP images:

Hyperplastic duct surrounded by cellular fibrous stroma

Apocrine hyperplasia

Focal nuclear pleomorphism and mitotic figures


Well circumscribed
tumor with leaf-like
ductal epithelium

Images hosted on other servers:

Hyperplastic ducts surrounded by cellular fibrous stroma

Circumscribed tumor

Leaf-like processes

Adjacent fibroadenoma

Low grade

Cysts containing papillary structures

Low grade phyllodes tumor

PASH-like changes in stroma

Myxoid background

Stroma is hyalinized

Nodular structure

Fibroblastic stromal cells are present

Adenosis-like appearance

Tubular epithelial elements

Epithelial hyperplasia


Positive stains
Electron microscopy description
  • Fibroblastic features
Molecular / cytogenetics description
Differential diagnosis
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