phyllodes tumor
Meaning of phyllodes tumor: An uncommon breast growth known for coming back in the same place, which is why the rim of tissue taken around it matters.
Definition of phyllodes tumor
A phyllodes tumor is an uncommon breast growth that arises from the connective tissue framework of the breast as well as from its ducts. Most are benign, but a minority behave aggressively and can spread through the bloodstream. Pathologists grade them as benign, borderline or malignant by looking at the cells and at the pattern of growth.
Where does the name come from?
Cut across, the tumor shows clefts lined by tissue that folds into them like the leaves of a book, and that leaf pattern gave the growth its name. An older label, cystosarcoma phyllodes, is still seen in reports and is misleading. Most of these growths are not sarcomas and never behave like cancer, so the newer name simply describes the pattern and leaves the grade to be stated separately.
How is it graded?
| Grade | What the pathologist sees | How it tends to behave |
|---|---|---|
| Benign | Orderly cells, few divisions, a well defined edge | Can regrow locally, does not spread |
| Borderline | Intermediate features | Regrows more often, spread is rare |
| Malignant | Crowded abnormal cells, many divisions, an edge that pushes into fat | Can spread through the blood, most often to the lungs |
How is it told apart from a fibroadenoma?
Both are made of gland and connective tissue, so a needle sample can look similar. The differences are ones of behavior and context. A fibroadenoma is common in young women and usually stays the same size for years. A phyllodes tumor typically appears a decade or two later, and the history that raises suspicion is a firm painless lump in the breast that has grown noticeably over weeks or months. Size alone does not settle it, and the diagnosis is often made only once the whole lump has been removed and examined.
Why does the margin matter?
These growths send fingers into the surrounding tissue, so shelling the lump out leaves cells behind and it returns in the same place. Removal with a cuff of normal tissue around it is what reduces that risk, and the width of that cuff is reported. Lymph nodes are rarely involved even in the malignant grade, because spread happens through the bloodstream rather than the lymphatic system, so node surgery is not part of the usual operation. Unlike a benign tumor of most other kinds, a benign phyllodes tumor still warrants follow up, because regrowth is possible and a recurrence occasionally comes back at a higher grade than the original.
Also known as
Used in a sentence
Wide local excision was performed for a rapidly enlarging breast mass reported as a benign phyllodes tumor.
Good to know
Most phyllodes tumors are benign, and the older name cystosarcoma phyllodes overstates the danger; the practical issue is regrowth at the same site, which is why the rim of normal tissue removed around the tumor is recorded.
Word origin
Where “phyllodes tumor” comes from
From the Greek phyllon, meaning leaf, and -odes, meaning like, after the leaf-shaped folds the tissue forms when the tumor is cut across.