Phyllodes tumour

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Phyllodes tumour
Diagnosis in short

Phyllodes tumour. H&E stain.

LM either (1) or (2): (1) large slit-like spaces, (2) cellular stroma - may be myxoid; +/-infiltrative border, +/-mitoses, +/-nuclear atypia, +/-"stromal overgrowth" ~ stroma fills microscopic field
Subtypes benign, borderline, malignant
LM DDx fibroadenoma, metaplastic breast carcinoma, primary breast sarcoma, other sarcomas
Gross mass with clefts - leaf-like structures
Site breast

Signs mass lesion
Prevalence uncommon
Prognosis usually benign, may be malignant
Clin. DDx other breast tumours - often fibroadenoma
Treatment wide excision

Phyllodes tumour is a tumour of the intralobular breast stroma. It may be benign or malignant.

It was previously called cystosarcoma phyllodes.

General

  • The name comes from the word "leaf".
    • With imagination or psychotropic drugs, it may look like one: the epithelial component = the veins of the leaf.
  • Wide excision -- this differs from fibroadenoma (just local excision).
  • Approximately 6% are malignant.[1]

Notes:

Gross

  • Clefts/leaf-like structures.
  • Friable - especially vis-à-vis a fibroadenoma.

Image:

Microscopic

Features - either 1, 2 or both of the following:

  1. Large slit-like spaces - key feature. †
  2. Cellular stroma - key feature. †
  • +/-Infiltrative border.
  • +/-Mitoses.
  • +/-Nuclear atypia.
  • +/-"Stromal overgrowth" ~ stroma fills microscopic field (see below).

Notes:

  • † Large slit-like spaces are required for a benign phyllodes tumour.
    1. Slit-like spaces may absent in a borderline phyllodes or a malignant phyllodes.
    2. A cellular tumour without features suggestive of malignancy and without slit-like spaces is a cellular fibroadenoma.
      • Some pathologists don't believe in cellular fibroadenoma - they call everything with stromal cellularity a phyllodes tumour.[4]

DDx:

Images

Grading

Phyllodes tumours are graded:

  • Benign.
  • Borderline.
  • Malignant.

Grading phyllodes tumours - based on WMSP:[5]

Feature Benign phyllodes Borderline phyllodes Malignant phyllodes
Circumscription Well Well Poor
Stromal overgrowth † none none may be present
Nuclear atypia mild mild-to-moderate moderate-to-marked
Mitoses per 10 HPFs < 5 5-10 >10
Heterologous elements +/- benign +/- benign +/- malignant
DDx fibroadenoma benign phyllodes, malignant phyllodes metaplastic breast carcinoma, sarcoma

Notes:

  • † Stromal overgrowth = epithelial elements absent in one low power field (LPF), defined as x40;[6] LPF is not adequately defined - see LPFitis.
  • HPF is not adequately defined - see HPFitis.

See also

References

  1. Guerrero MA, Ballard BR, Grau AM (July 2003). "Malignant phyllodes tumor of the breast: review of the literature and case report of stromal overgrowth". Surg Oncol 12 (1): 27–37. PMID 12689668. http://linkinghub.elsevier.com/retrieve/pii/S0960740403000057.
  2. Bannowsky, A.; Probst, A.; Dunker, H.; Loch, T. (2009). "Rare and challenging tumor entity: phyllodes tumor of the prostate.". J Oncol 2009: 241270. doi:10.1155/2009/241270. PMID 20069045.
  3. McCluggage, WG. (Mar 2010). "Mullerian adenosarcoma of the female genital tract.". Adv Anat Pathol 17 (2): 122-9. doi:10.1097/PAP.0b013e3181cfe732. PMID 20179434.
  4. URL: http://www.breastpathologyconsults.com/blog/wp-content/uploads/2011/03/FEL_poster.pdf. Accessed on: 23 February 2012.
  5. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 263. ISBN 978-0781765275.
  6. Taira N, Takabatake D, Aogi K, et al (October 2007). "Phyllodes tumor of the breast: stromal overgrowth and histological classification are useful prognosis-predictive factors for local recurrence in patients with a positive surgical margin". Jpn. J. Clin. Oncol. 37 (10): 730-6. doi:10.1093/jjco/hym099. PMID 17932112. http://jjco.oxfordjournals.org/cgi/reprint/37/10/730.