Fact-sheet: Phyllodes tumor
Updated on 02/22/2021 at 4:23 PM
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Definition
Fibroepithelial tumor with the features of a fibroadenoma but with a predominant hypercellular stromal component.
They are most often benign (60 to 70%).
Malignant forms (grade 3) "phyllodes sarcomas" are among the primary sarcomas of the breast.
They are considered a distinct group of rare neoplasms: 0.3 to 1% of breast neoplasms.
Clinical features
No pathognomonic clinical or radiologic sign, but suggestive findings:
- Rapid growth of a known benign tumor or a recent increase in breast size
- Palpable tumors, as they are large (discovered when they measure 3 to 5 cm), firm, and more or less rubbery.
In grade 1 lesions, the clinical criteria of benignity are found: regular margins, round or lobulated shape, and mobility.
Skin changes (erythema, shiny inflamed skin, stretch marks) are found only when the tumor size is large or when the tumor is superficially located.
They are solitary in 85% of cases.
Radiography
There is no correlation between the radio-clinical features and the histological classification.
Mammography:
-In grade 1 phyllodes tumors, the semiologic criteria of a typically benign mass such as fibroadenoma are found: Round, oval, or lobulated shape/Well-defined margins/High density.
Ultrasound
Grade 1 phyllodes tumors: semiologic criteria of a typically benign mass such as fibroadenoma = -
Oval or round mass -
Circumscribed or lobulated margins -
Homogeneous echostructure with occasional posterior enhancement -
Good compressibility -
Intralesional cystic areas
Elastography showing a target-like pattern with a soft center and a harder periphery.
MRI
- Features favoring malignancy:
irregular margins - high T1 signal (necrosis and hemorrhage)
- T2 hyposignal
- Cystic changes
- Features favoring benignity: round and lobulated shape
- T2 hypersignal
- septa without enhancement after gadolinium injection
Management
The diagnosis is histopathological.
There is no radiologic criterion that can differentiate a benign phyllodes tumor from a fibroadenoma.
Treatment:
Wide excision with clear margins for grades 1 and 2.
Mastectomy + radiotherapy for grade 3.
Annual clinical, mammographic, and sonographic follow-up is required for 5 years.
If grade 3 = phyllodes sarcoma --> CT follow-up to look for lymph node and pulmonary metastases
Differential diagnosis
- Fibroadenoma
- Invasive breast carcinoma