Phyllodes Tumour Management
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Direct answer
Like a fibroadenoma, only a decade older and in a hurry: the phyllodes tumour is a fibroepithelial neoplasm of women typically in their forties, presenting as a rapidly enlarging breast lump — often a long-standing "fibroadenoma" that suddenly grows — with leaf-like epithelial clefts and a cellular stroma that decides behaviour. Grading into benign, borderline and malignant rests on stromal cellularity, atypia, mitotic activity and stromal overgrowth. Treatment is wide local excision with a margin of at least 1 cm; axillary dissection is not performed even for malignant phyllodes, because it spreads haematogenously — to lung and bone — not through lymphatics.
What you must remember
- Age signature: fibroadenoma in the twenties, phyllodes in the forties (a viva shorthand examiners reward); a "fibroadenoma" enlarging quickly in a middle-aged woman is a phyllodes until proven otherwise.
- Macroscopy: circumscribed, lobulated, grey-white with whorled clefts; microscopy: leaf-like papillae lined by benign epithelium over a hypercellular stroma — the stroma is the tumour.
- Grading: benign (mild cellularity, few mitoses), borderline (moderate atypia and mitotic activity) and malignant (marked stromal overgrowth, severe atypia, frequent mitoses) — metastatic potential rises with grade.
- The margin is the operation: at least 1 cm of healthy tissue, because the tumour's pseudocapsule invites local recurrence when enucleated; recurrence even of benign histology is well recognised.
- No axillary dissection: nodal metastasis is rare (a small percentage) — verify clinically, but the spread is haematogenous, with lung the commonest distant site, then bone.
- Mastectomy is reserved for tumours too large for breast-conserving clearance, for recurrent disease, or where margins cannot be achieved relative to breast size.
- Core biopsy (not FNAC) before surgery: cytology cannot reliably separate cellular fibroadenoma from phyllodes; imaging may show a rapidly growing lobulated solid mass.
- Local recurrence is managed by re-excision with wider margins; distant metastases from malignant phyllodes behave like soft-tissue sarcoma and are treated systemically.
- Giant phyllodes may ulcerate the skin with dilated overlying veins — and are still, in a proportion, histologically benign.
Deciding the operation for a fast-growing lump
A 46-year-old reports that a lump known for six years has doubled in size over five months; examination finds an 8 cm, smooth, mobile mass with a prominent vein but no nodes. Core biopsy reports a spindle-cell fibroepithelial tumour favouring benign phyllodes, with the caveat that grading requires the whole lesion — the clinical hinge, since definitive classification comes from the excised specimen.
Because the tumour is 8 cm in a moderate breast, achieving a 1 cm margin by wide local excision is feasible but will distort the breast; oncoplastic planning (therapeutic mammoplasty or local tissue rearrangement) lets the surgeon take generous margins without mutilation. The definitive histology reports benign phyllodes, completely excised — she is surveyed clinically and by imaging, with counselling that recurrence, usually local, occurs in a minority even after adequate excision.
Vary the histology to malignant with stromal overgrowth and a 15 cm size: the discussion moves to mastectomy (breast conservation rarely achieves margins), still with clinical axillary assessment rather than dissection, and a staging chest CT — because the threat in malignant phyllodes is haematogenous, to the lungs, exactly like a sarcoma.
Where students slip
The commonest error is enucleation — shelling the tumour out "like a fibroadenoma" through its pseudocapsule; local recurrence of phyllodes after enucleation is the standard cautionary tale, and the examined answer is a 1 cm margin. The second is the reflex to operate on the axilla: malignant-sounding breast tumour plus no nodes still does not justify clearance, and the candidate who explains the haematogenous, sarcoma-like biology of malignant phyllodes — lung secondaries, node-negative — demonstrates the concept rather than the reflex. The third is diagnostic: trusting FNAC to distinguish cellular fibroadenoma from phyllodes; cores, and often the whole specimen, make that call.
Frequently asked questions
In which age group does phyllodes tumour typically occur?
Most often in the forties — about two decades after the peak of fibroadenoma — and rapid growth of a long-standing lump in this age group is the classic history.
On what features is phyllodes tumour graded?
Stromal cellularity, nuclear atypia, mitotic activity and stromal overgrowth define benign, borderline and malignant categories, which predict local recurrence and metastatic behaviour.
What margin is required at excision?
At least 1 cm of healthy tissue around the tumour; enucleation along the pseudocapsule invites local recurrence even in histologically benign lesions.
Is axillary dissection indicated in malignant phyllodes?
No — spread is haematogenous rather than lymphatic, nodal metastasis is rare, and the axilla is assessed clinically; dissection is reserved for the exceptional proven nodal disease.
Where does malignant phyllodes metastasise?
Haematogenously, behaving like a soft-tissue sarcoma — lung is the commonest site, followed by bone — with metastases managed systemically.
When is mastectomy chosen?
For tumours too large relative to the breast to achieve 1 cm clear margins with conservation, for local recurrence where further breast preservation is impossible, or at patient preference after counselling.