A phyllodes tumor is an abnormal mass that grows in the connective tissue of the breast, unlike the much-more-common carcinoma, which grows in the ducts or lobules. Its name derives from the Greek word "phullon," which means "leaf," because it grows in a leaf-like pattern. Phyllodes tumors are usually large and fast-growing, sometimes developing in a few weeks, but are unlikely to spread beyond the breast. Malignant phyllodes tumors are extremely rare, making up less than one percent of all breast cancers, but all phyllodes tumors have the potential to become malignant. Phyllodes tumors rarely affect adolescent girls, elderly women or men.
Types of Phyllodes Tumors
Phyllodes tumors are divided into three types: benign, borderline and malignant. The majority of phyllodes tumors are benign, with the remainder divided fairly evenly between borderline and malignant.
Risk Factors for Phyllodes Tumors
The following may increase the risk of developing phyllodes tumors:
- Early menarche
- Late menopause
- Being older than 40
- Having hormone-replacement therapy
- Having a first child at 30 or older
- Family history of phyllodes tumors
- Genetic predisposition
Symptoms of Phyllodes Tumors
The most common symptom of a phyllodes tumor is a firm yet usually painless lump. If left untreated, the lump can be seen pushing against the skin. In advanced cases, whether the tumor is benign, borderline or malignant, an ulcer or open wound may form on the breast. As a result, even if a phyllodes tumor is determined to be benign, the recommendation is usually to remove it.
Diagnosis of Phyllodes Tumors
A phyllodes tumor may be difficult to diagnose because of its rarity, and because it often resembles a fibroadenoma, which is the most common type of growing but normal breast mass. In addition to a doctor-performed physical exam, the following tests may be performed to help diagnose a phyllodes tumor:
- MRI scan
- Core needle biopsy
- Excisional biopsy
Treatment of Phyllodes Tumors
Excision is the only treatment for malignant phyllodes tumors because they do not respond to the hormone therapy, radiation and chemotherapy used to treat more common types of breast cancer. Treatment for a malignant phyllodes tumor usually involves a lumpectomy, which removes the tumor and a wide margin of healthy tissue surrounding it. Treatment for a benign phyllodes tumor usually involves removing the tumor and a smaller margin of healthy tissue. Healthy tissue is excised in both cases because phyllodes tumors have a tendency to grow back unless all the affected cells are removed.
A partial or total mastectomy may be performed if the tumor is very large and/or the breast is very small, making it difficult to save enough tissue to retain the natural look of the breast.
Frequent breast exams and imaging tests are usually recommended post-treatment because of the possibility of recurrence. Malignant phyllodes tumors rarely tend to metastasize.