Phyllodes Tumors of the Breast: Diagnosis, Treatment & Management

A young woman stands in solidarity with the fight against breast cancer wearing a T-shirt with the icon ribbon.

By Kevin FamuyiroSenior Content Strategist

March 13, 2025 12:04 PM PT

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Phyllodes tumors, are rare breast tumors made up of stromal and epithelial tissues, and are fibroepithelial neoplasms known for fast growth and recurrence. They are classified into benign, borderline and malignant based on cellular characteristics. Benign phyllodes tumors, which are the majority, do not increase breast cancer risk, though borderline tumors show intermediate features, while malignant phyllodes tumors have higher recurrence and spread risks.

Table of Contents

What are Phyllodes Tumors?
Types of Malignant Phyllodes Tumors
Epidemiology and Risk Factors
Pathophysiology of Malignant Phyllodes Tumors
Epidemiology and Classification
Diagnosis
Treatment and Breast Conserving Surgery
Complications and Side Effects of Treatment
Prognosis and Local Recurrence
Patient Education and Support
Closing Thoughts
References

What are Phyllodes Tumors?

Phyllodes tumors are a rare type of breast tumor, accounting for 1% of all breast tumors. Also known as cystosarcoma phyllodes or fibrosarcoma of the breast, these tumors have a leaf-like or villous pattern. Phyllodes tumors can be classified into three categories: benign, borderline and malignant based on their cellular characteristics and behavior. While the exact cause of phyllodes tumors is unknown, they are believed to arise from the stromal cells of the breast. These tumors can grow fast and recur after treatment, so accurate diagnosis and management is key. Understanding breast phyllodes tumors is important for developing treatment plan and improving patient outcomes.

Types of Malignant Phyllodes Tumors

Doctors classify phyllodes tumors into three main types based on what pathologists see under the microscope. These are: Most phyllodes tumors are benign, which means they have good prognosis and lower risk of recurrence.

Benign – These have fewer dividing cells and mild or no abnormal changes.
Borderline – These show characteristics between benign and malignant, meaning moderate cell growth and changes.
Malignant – These have high cell growth, noticeable changes and higher chance of spreading or coming back. Since phyllodes tumors look like common fibroadenomas (a more common benign breast lump), accurate diagnosis is important. Correct diagnosis ensures right treatment plan. Studies have shown that tailored treatment which may include surgery and other therapies can reduce recurrence and improve patient outcomes.

Epidemiology and Risk Factors

Phyllodes tumors are most common in women in their 40s but can occur at any age. Certain risk factors have been identified that may increase the risk of developing these tumors. Women with Li-Fraumeni syndrome, a rare genetic condition, have higher risk of phyllodes tumors. Family history of breast cancer and previous radiation exposure are also risk factors. While phyllodes tumors are rare in men, they can occur in men with gynecomastia, a condition where breast tissue develops in men. Understanding these risk factors can help in early detection and management of phyllodes tumors and better patient outcomes.

Pathophysiology of Malignant Phyllodes Tumors

Malignant phyllodes tumors are characterized by high cellularity, pleomorphism and high risk of metastasis. Unlike benign phyllodes tumors, malignant variants show mitotic figures, cellular atypia and stromal overgrowth. These histopathological features indicate aggressive behavior and higher chance of spreading to other parts of the body. Malignant phyllodes tumors can metastasize to lungs, bones and brain and has poor prognosis. Understanding the pathophysiology and histopathology of malignant phyllodes tumors is important for developing treatment plan and improving patient survival.

Epidemiology and Classification

Phyllodes tumors is not as common as other breast tumors. According to one 10-year retrospective study, benign phyllodes tumors account for about 62% of all phyllodes tumors ^[⁶^]. Borderline and malignant tumors are less common but can still be challenging if not diagnosed and treated properly.

The classification guide doctors on how aggressive to treat the tumor especially in terms of surgical margins (the amount of normal tissue taken around the tumor during surgery) and if additional therapy like radiation therapy is needed.

Diagnosis

Preoperative Diagnostic Tools

Ultrasound: This imaging test uses sound waves to get an image of what is happening inside the breast. It can help identify the shape and borders of a phyllodes tumor. Sometimes phyllodes tumors have a leaf-like pattern which is a clue to its identity.
MRI (Magnetic Resonance Imaging): MRI can create detailed images of soft tissues and often provides more information if a tumor looks suspicious or if a doctor needs a clearer view before surgery. This is especially helpful when other imaging tests are not clear.
Core Needle Biopsy: This is a very important step. A doctor uses a special needle to take a small tissue sample from the breast lump. A pathologist then examines the tissue under the microscope to look for features that indicate if the tumor is benign, borderline or malignant ^[²^].

Diagnostic Criteria

While the current World Health Organization (WHO) guidelines help classify malignant phyllodes tumors (MPTs), studies suggest that these guidelines sometimes fail to catch all cases that will later metastasize. Newer studies have proposed refined criteria to improve the chances of detecting phyllodes tumors with aggressive potential ^[⁵^]. This research aims to reduce the rate of missed diagnoses so that treatments can be adjusted sooner for patients who may have a higher risk of metastasis.

Diagnosis involves imaging tests like ultrasound or MRI and core needle biopsy. Treatment is focused on removal with clear margins to reduce recurrence, and radiation therapy for malignant cases. Despite their rarity, managing phyllodes tumors requires a personalized approach for better outcomes.

Treatment and Breast Conserving Surgery

Most people with phyllodes tumors will need surgery to remove the tumor. According to a study published in Breast Cancer Res Treat, various treatment approaches and management strategies are important for better patient outcomes. How much tissue to be removed and if additional therapy is needed depends on factors like the tumor’s category (benign, borderline or malignant), size of the tumor and how close it is to the surrounding normal breast tissue.

Surgical Management

Margins: Research shows that removing at least one centimeter (about half an inch) of normal tissue around the tumor can reduce the chance of the tumor coming back ^[¹^]. For some, getting this clear margin may mean removing more breast tissue depending on where the tumor is located and its size relative to the breast.
Breast Conservation: Breast-conserving surgery (BCS) removes only the tumor and a rim of normal tissue instead of the whole breast. This can be done for all grades of phyllodes tumors. However, if the tumor is malignant, there may be a higher chance it will come back compared to more extensive surgery ^[²^]. Each patient’s case is different so surgeons weigh the risks and benefits with the patient.
Mastectomy vs. BCS: Removing the whole breast (mastectomy) may be necessary for very large tumors or if a clear margin would be difficult to achieve otherwise. A single-institution study showed that for malignant phyllodes tumors, there was no significant difference in 5-year disease-free survival rates between mastectomy and breast-conserving surgery ^[⁷^]. This means BCS might be an option for some malignant cases as long as surgical margins are adequate.

Adjuvant Therapy

Radiotherapy: Radiotherapy is often recommended for malignant tumors especially if the doctors are worried about the tumor coming back. Research supports that postoperative radiotherapy can significantly reduce the chance of recurrence in malignant tumors ^[¹^]. This is because radiotherapy can kill any cancer cells left behind after surgery.
Systemic Therapy for Metastatic Disease: If the tumor has metastasized beyond the breast, chemotherapy may be used. Studies have shown that regimens containing ifosfamide, a type of chemotherapy drug, have the longest progression-free survival in metastatic phyllodes tumor cases ^[³^]. Chemotherapy aims to reach cells that have spread to other parts of the body and keep them from growing or coming back.

Complications and Side Effects of Treatment

Phyllodes tumors treatment can have various complications and side effects depending on the type of treatment given. Surgical removal of the tumor can cause scarring, infection and breast shape and size changes.

Radiotherapy, often recommended for malignant phyllodes tumors, can cause fatigue, skin changes and secondary cancers. Chemotherapy used for metastatic disease can cause nausea, vomiting and hair loss. Patients with malignant phyllodes tumors may also experience metastasis which greatly affects their prognosis.

Patients should be aware of these potential complications and side effects to make informed decisions about their treatment options.

Prognosis and Local Recurrence

Recurrence Rates

Phyllodes tumors have different rates of coming back based on its classification and margins during surgery. A systematic review broke down the recurrence rates as follows:

Benign: 7.1%
Borderline: 16.7%
Malignant: 25.1%

These numbers show that benign tumors have the lowest recurrence rate and malignant tumors have the highest rate of coming back ^[¹^]. Local recurrence rates are influenced by the tumor classification and the adequacy of surgical margins, that’s why getting enough normal breast tissue around the tumor (achieving wide margins) is very important.

Risk Factors for Recurrence

Some factors can increase the chance of a tumor coming back. One is younger age, younger patients have higher recurrence rate. Another is malignant histology, tumors already classified as malignant are more prone to come back ^[⁶^]. Knowing these risk factors helps doctors and patients plan for follow-up visits and imaging tests.

Patient Education and Support

Patient education and support is important in the management of phyllodes tumors. Patients should be informed about their diagnosis, treatment options and complications and side effects. Encouraging patients to participate in follow-up care and regular screening is crucial in detecting any recurrence or metastasis early. Support groups and counseling services can provide emotional and psychological support to patients to cope with their diagnosis and treatment. By providing comprehensive education and support, healthcare providers can empower patients to take an active role in their care and improve their quality of life.

Clinical Practice Variations

Despite guidelines and studies, phyllodes tumors management varies from one hospital or region to another. One international study showed there is no universal agreement on some critical points:

How to achieve surgical margins.
When and how to use additional therapy like radiotherapy.
How long and how often follow-up visits should be done ^[⁴^].

This lack of consensus can result to different experiences for patients in different places. The complexity of cancerous phyllodes tumors emphasizes the need for standardized treatment approaches to ensure uniform patient outcome. Some doctors rely more on their personal experience while others follow published guidelines. Ongoing research aims to establish clearer guidelines so treatment methods around the world can be uniform.

Closing Thoughts

Phyllodes tumors of the breast are rare fibroepithelial neoplasms that pose challenges due to its rapid growth and recurrence. Unlike breast cancers that arises from ducts or glands, phyllodes tumors arises from the connective tissue and requires different management. These tumors are classified into benign, borderline and malignant, surgical excision is the primary treatment. Individualized treatment plan is necessary considering tumor size, location and patient’s history and ongoing research aims to fine tune management and improve outcome.

References

^{[1] Yu, C. Y., Huang, T. W., & Tam, K. W. (2022). Management of phyllodes tumor: A systematic review and meta-analysis of real-world evidence.}^{International journal of surgery (London, England)}^,¹⁰⁷^{, 106969.}^{https://doi.org/10.1016/j.ijsu.2022.106969}

^{[2] Bogach, J., Shakeel, S., Wright, F. C., & Hong, N. J. L. (2022). Phyllodes Tumors: A Scoping Review of the Literature.}^{Annals of surgical oncology}^,²⁹^{(1), 446–459.}^{https://doi.org/10.1245/s10434-021-10468-2}

^{[3] Parkes, A., Wang, W. L., Patel, S., Leung, C. H., Lin, H., Conley, A. P., Somaiah, N., Araujo, D. M., Zarzour, M., Livingston, J. A., Ludwig, J., Roland, C. L., Ravi, V., Benjamin, R. S., & Ratan, R. (2021). Outcomes of systemic therapy in metastatic phyllodes tumor of the breast.}^{Breast cancer research and treatment}^,¹⁸⁶^{(3), 871–882.}^{https://doi.org/10.1007/s10549-021-06116-8}

^{[4] Sars, C., Sackey, H., Frisell, J., Dickman, P. W., Karlsson, F., Kindts, I., Marta, G. N., Freitas-Junior, R., Tvedskov, T. F., Kassem, L., Ali, A. S., Ihalainen, H., Neron, M., Kontos, M., Kaidar-Person, O., Meattini, I., Francken, A. B., van Duijnhoven, F., Moberg, I. O., Marinko, T., … Lindqvist, E. K. (2023). Current clinical practice in the management of phyllodes tumors of the breast: an international cross-sectional study among surgeons and oncologists.}^{Breast cancer research and treatment}^,¹⁹⁹^{(2), 293–304.}^{https://doi.org/10.1007/s10549-023-06896-1}

^{[5] Turashvili, G., Ding, Q., Liu, Y., Peng, L., Mrkonjic, M., Mejbel, H., Wang, Y., Zhang, H., Zhang, G., Wang, J., Wei, S., & Li, X. (2023). Comprehensive Clinical-Pathologic Assessment of Malignant Phyllodes Tumors: Proposing Refined Diagnostic Criteria.}^{The American journal of surgical pathology}^,⁴⁷^{(11), 1195–1206.}^{https://doi.org/10.1097/PAS.0000000000002109}

^{[6] Ditsatham, C., & Chongruksut, W. (2019). Phyllodes tumor of the breast: diagnosis, management and outcome during a 10-year experience.}^{Cancer management and research}^,¹¹^{, 7805–7811.}^{https://doi.org/10.2147/CMAR.S215039}

^{[7] Mituś, J., Reinfuss, M., Mituś, J. W., Jakubowicz, J., Blecharz, P., Wysocki, W. M., & Skotnicki, P. (2014). Malignant phyllodes tumor of the breast: treatment and prognosis.}^{The breast journal}^,²⁰^{(6), 639–644.}^{https://doi.org/10.1111/tbj.12333}