# Phyllodes tumour of the breast

Source: https://onco.cc/cancers/phyllodes-tumour/  
OnCo record `phyllodes-tumour` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A phyllodes tumour is a fast-growing, usually painless breast lump of gland and connective tissue that forms leaf-like fronds. Most are benign, some borderline and a few malignant, behaving like a sarcoma and spreading through the blood. Treatment is surgery with a rim of normal tissue; radiotherapy is considered for higher grades, and chemotherapy has little proven role.

## Summary

Phyllodes tumours are fibroepithelial tumours in which the stroma, not the epithelium, is the neoplastic component; the epithelium is stretched into the leaf-like clefts that give the name. The World Health Organization grades them benign, borderline or malignant on stromal cellularity, nuclear atypia, mitotic count, stromal overgrowth and the character of the border, and most are benign. They present as a smooth, mobile, often large lump that has grown quickly over months, in women a decade older than those with fibroadenoma. Imaging cannot reliably separate the two, and a core biopsy often returns only a fibroepithelial lesion, so any rapidly growing or large fibroepithelial lesion is excised for diagnosis. Benign phyllodes tumours and fibroadenomas share MED12 mutations, and TERT promoter mutations accumulate in borderline and malignant tumours.

Surgery is the treatment for every grade. Wide local excision with clear margins is the aim, and mastectomy is reserved for tumours too large for the breast; the traditional demand for a 1 cm margin has softened, and guidelines now accept any negative margin for benign tumours while recommending re-excision for positive margins in borderline and malignant disease. Lymph node metastases are rare, so sentinel node biopsy and axillary dissection are not performed. Adjuvant radiotherapy has no randomised evidence: a single-arm phase 2 study of 46 borderline and malignant tumours treated with margin-negative breast-conserving surgery and radiotherapy reported no local recurrences, and guidelines list radiotherapy as a consideration after breast conservation for these grades. Adjuvant chemotherapy has no proven benefit and hormone receptors, though often present in the epithelium, do not guide treatment.

Benign tumours are cured by excision and recur locally in a minority, often at a higher grade than the original. Malignant tumours recur locally more often and a substantial minority metastasise, most often to the lungs and bone within the first few years, at which point they are treated like soft-tissue sarcomas with doxorubicin-based chemotherapy, and survival after recurrence is short. Follow-up with examination and imaging for the first few years catches most recurrences. The rarity of the disease means margin width, the role of radiotherapy and the value of molecular grading rest on retrospective series and registries rather than trials.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: Cystosarcoma phyllodes (historical); Fibroepithelial tumour of the breast; Malignant phyllodes tumour
- Tags: subtype-page
- Group: breast
- Burden: Under one percent of breast tumours, typically in women in their forties, a decade later than fibroadenoma; most are benign, and only the malignant minority behave as sarcomas and spread.
- Subtypes: Benign phyllodes tumour (most; excision alone); Borderline phyllodes tumour (wide excision, radiotherapy considered); Malignant phyllodes tumour (sarcoma-like; wide excision or mastectomy, radiotherapy, sarcoma chemotherapy if metastatic); Phyllodes tumour with heterologous sarcomatous elements (liposarcoma, osteosarcoma); Recurrent phyllodes tumour (often a higher grade than the original)
- Biomarkers: WHO grade from stromal cellularity, atypia, mitotic count, stromal overgrowth and border (benign, borderline, malignant); Margin status after excision; Tumour size relative to the breast; MED12 mutation (shared with fibroadenoma) and TERT promoter mutation (borderline and malignant); No routine hormone receptor or HER2 testing (stroma-driven tumour); Chest CT for metastases in malignant tumours

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/phyllodes-tumour/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/phyllodes-tumour/#overview [3 state-of-the-art points]
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/phyllodes-tumour/#what-it-is [5 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/phyllodes-tumour/#finding-it [6 biomarkers]
- Treatment (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/phyllodes-tumour/#treating-it [4 settings, 1 decision with options]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/phyllodes-tumour/#evidence [2 key papers, 4 milestones]
- Biology and targets (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/phyllodes-tumour/#science
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/phyllodes-tumour/where-you-are/ [16 UK centres]
- Decisions and support (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/phyllodes-tumour/#living-with-it [14 questions, 6 red cards]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/phyllodes-tumour/coming/ [1 medicine, 4 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/phyllodes-tumour/data/ [14 connected records]

## Standard of care

- Diagnosis: Ultrasound and mammography, core needle biopsy, and excision of any rapidly growing or large fibroepithelial lesion because biopsy cannot reliably separate phyllodes tumour from fibroadenoma. ([Ultrasound](https://onco.cc/technologies/ultrasound/), [Mammography & tomosynthesis](https://onco.cc/technologies/mammography/), [Core needle biopsy and fine-needle aspiration (FNA)](https://onco.cc/terms/core-needle-biopsy/), [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/))
- Benign phyllodes tumour: Complete excision with clear margins; observation if margins are close after a benign diagnosis. ([Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/))
- Borderline and malignant phyllodes tumour: Wide excision aiming for clear margins or mastectomy for large tumours, no axillary staging, and adjuvant radiotherapy considered after breast conservation. ([Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Mastectomy](https://onco.cc/terms/mastectomy/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/))
- Metastatic malignant phyllodes tumour: Treated as a soft-tissue sarcoma with doxorubicin-based chemotherapy; no proven benefit from adjuvant chemotherapy. ([Doxorubicin](https://onco.cc/drugs/doxorubicin/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/))

## State of the art

- Margin requirements have relaxed for benign tumours, sparing breast tissue.
- Molecular grading with TERT promoter and other mutations is being tested against histology.
- Radiotherapy after breast conservation is accepted as an option for borderline and malignant tumours on single-arm evidence.

## Open problems

- No randomised trial has tested margin width or radiotherapy.
- Core biopsy cannot reliably distinguish phyllodes tumour from fibroadenoma.
- Metastatic malignant phyllodes tumour has no effective systemic therapy.
- Grading is subjective at the benign-borderline and borderline-malignant boundaries.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Phyllodes_tumor
- NCCN Guidelines: Breast Cancer (phyllodes tumour section): https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1419
- Wikipedia: https://en.wikipedia.org/wiki/Phyllodes_tumor

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Ductal carcinoma in situ (DCIS)](https://onco.cc/cancers/ductal-carcinoma-in-situ/), [Male breast cancer](https://onco.cc/cancers/male-breast-cancer/), [Paget disease of the nipple](https://onco.cc/cancers/paget-disease-of-the-nipple/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/)
- bottlenecks: [Rare and paediatric cancers without markets](https://onco.cc/bottlenecks/b-rare-cancers/)
- key papers: [Phyllodes tumours of the breast: a consensus review](https://onco.cc/key-papers/paper-tan-phyllodes-consensus-histopathology-2016/), [Prospective multi-institutional study of adjuvant radiotherapy after resection of borderline and malignant phyllodes tumours](https://onco.cc/key-papers/paper-barth-phyllodes-adjuvant-radiotherapy-ann-surg-oncol-2009/)
- technologies: [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Mammography & tomosynthesis](https://onco.cc/technologies/mammography/), [Ultrasound](https://onco.cc/technologies/ultrasound/)
- terms: [Core needle biopsy and fine-needle aspiration (FNA)](https://onco.cc/terms/core-needle-biopsy/), [Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Mastectomy](https://onco.cc/terms/mastectomy/), [The WHO classification of breast tumours, and what the 6th edition changed](https://onco.cc/terms/who-breast-classification/)
- drugs: [Doxorubicin](https://onco.cc/drugs/doxorubicin/)

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JSON: https://onco.cc/api/v1/entities/phyllodes-tumour.json