Breast - nonmalignant
Benign tumors / changes
Phyllodes tumor - malignant

Author: Hind Nassar, M.D. (see Authors page)

Revised: 10 August 2017, last major update April 2010

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Breast [title] phyllodes malignant [title] tumor

See also: Phyllodes - generalPhyllodes - benignPhyllodes - borderline

Cite this page: Nassar, H. Phyllodes tumor - malignant. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastphyllodesmalignant.html. Accessed November 21st, 2017.
Definition / general
  • Phyllodes tumors with increased mitotic activity, stromal overgrowth, atypia and infiltrative borders
Terminology
  • Also called high grade
Epidemiology
  • 10% of phyllodes tumors; very rare under age 20 years
Etiology
Clinical features
  • Aggressive with local recurrence, 3 - 22% metastasize to lung, bone, CNS
  • Metastases are stromal but may entrap normal epithelium
  • Death from disease is associated with recurrences and distant metastases (Am J Clin Pathol 2005;123:529)
  • Better prognosis than invasive ductal carcinoma (Am Surg 2007;73:967)
Prognostic factors
  • Poor prognostic factors: tumor necrosis, stromal elements other than fibromyxoid
Case reports
Treatment
Gross images

Images hosted on other servers:

Tumors with hemorrhage and necrosis

Malignant

Microscopic (histologic) description
  • > 10 mitotic figures per 10 high per fields AND stromal > ductal overgrowth (no ducts at 4x), densely packed anaplastic stromal cells and infiltrative border
  • Also tumor necrosis, heterologous stromal elements, may have cellular stroma only around blood vessels
  • Note: stroma is the malignant component and may be present in only part of the tumor so sample thoroughly
  • Stroma may resemble MFH, fibrosarcoma, liposarcoma (Am J Surg Pathol 1994;18:720), osteosarcoma (Am J Surg Pathol 1999;23:815), cartilage, skeletal muscle
  • Higher Ki67 immunostaining than benign phyllodes tumors (Mod Pathol 2001;14:185)
Microscopic (histologic) images

Scroll to see all images:


Images hosted on PathOut server:

Multinucleated giant cells

Squamous metaplasia and keratin cysts

Osteochondroid metaplasia

Liposarcoma component

Hypercellular
tumor with stromal
overgrowth, atypia
and mitotic figures



Images hosted on other servers:

Squamous metaplasia and keratin cysts

Sarcomatous stroma

Pleomorphic nuclei

Infiltration into adipose tissue

Mitotic figures and abnormal mitotic figure


Multinucleated giant cells

Chondrosarcoma component

Fibrosarcomatous stroma


Liposarcoma component

MFH component

Osteosarcoma component


Rhabdomyosarcoma component

Sarcoma NOS component



Contributed by Dr. Semir Vranić


Metastasis to thyroid Hürthle cell tumor

Ki67 - Fig A: Benign tumor with minimal nuclear staining
Fig B: Low grade malignant tumor with increased Ki67
Fig C: High grade malignant tumor with frequent staining


p53+

p53

c-kit+ stromal cells and stromal giant cells

Cytology description
  • Epithelial cells, isolated spindled or round cells, phyllodes fragments, spindle cells within stroma, bipolar naked nuclei
  • Epithelial cells may overwhelm sarcomatous component (Diagn Cytopathol 2004;31:71)
Positive stains
Molecular / cytogenetics description
Differential diagnosis