Phyllodes Tumours

Phyllodes tumours are uncommon tumours that are usually benign, however rarely malignant phyllodes tumours may be seen. Phyllodes tumours may present as a palpable lump, or lobulated mass seen on ultrasound or mammogram. Clinically they often present like a fibroadenoma which is the main differential diagnosis and both fibroadenomas and phyllodes tumours are grouped together as fibroepithelial lesions. They may be seen in a broad age group from teenagers to the elderly however the peak presentation is in the 40- 50 age group. Fibroadenomas tend to occur more commonly a decade or two younger. There are no known risk factors for phyllodes tumours.

Phyllodes tumours maybe suspected based on a clinical history of a rapidly growing lump in the breast or a large or lobulated (lumpy outline) mass seen on ultrasound. These tumours maybe difficult to distinguish from fibroadenomas on needle biopsy, either fine needle biopsy or core biopsy, partly due to the fact that there can be variable areas of change within the lesion (heterogeneity). Because of this difficulty, if a patient presents with a rapidly enlarging lump thought to be a fibroadenoma, then removal of the lump should be considered. Under the microscope phyllodes tumours will have a stromal component (supporting tissue network) and an epithelial component (layer lining the milk ducts). The stromal component is often quite cellular distinguishing it from fibroadenomas. If there is enough change in the appearance of the cells in the stroma (atypia) then the tumour maybe diagnosed as a malignant phyllodes. These are however quite rare. Those with partial or equivocal malignant features may be termed borderline.



Types of Phyllodes Tumours

1. Benign - majority of lesions
2. Borderline
3. Malignant - rare

Treatment of a phyllodes tumour is surgical removal. It is essential that there is a clear margin of tissue between the tumour and the edge of the excision as there is a risk of local regrowth (local recurrence) of these lesions. Sometimes if local recurrence occurs the lesion may be more aggressive or malignant. Malignant Phyllodes are a type of sarcoma ( aggressive cancer ) and may require radical treatment such as mastectomy and Radiotherapy. Malignant Phyllodes tumours tend to spread via the bloodstream so that removal of the lymph nodes is not usually necessary.

Because of the risk of local recurrence, it is important to follow up patients with regular imaging. Ultrasound every 6 to 12 months and in patients over 40 annual mammography is important. The biggest risk of recurrence is within the first three years of diagnosis.