Many phyllodes tumors are benign (35%-64%) and can be treated with local excision. The remainder of tumors are divided between borderline and malignant (25%).1,2 The fastest growing tumors tend to be malignant, are more likely to metastasize to other areas, and are more likely to recur after treatment.1

Patients most often present with skin stretched taunt over a rapidly growing tumor. The median size of phyllodes tumors is approximately 4 cm.7 Twenty percent of tumors can grow larger than 10 cm, termed giant phyllodes, with some reaching 20 cm to up to 40 cm. Nipple retraction and ulceration are rarely seen. The tumors are most commonly found in the upper quadrant of either the right or left breast and rarely occur bilaterally.7 Positive lymph nodes occur in less than 1% of cases. Patients with phyllodes tumors commonly have a history of fibroadenomas.7-9

On mammography, phyllodes tumors appear to be large, round masses with smooth, polylobulated well-defined borders (Figure). Ultrasonography findings of the breast tumor may mimic that of fibroadenomas; the tumors are usually well circumscribed with smooth margins with fluid-filled clefts in a sold mass. A core needle biopsy of the tumor often reveals stromal cells but can also contain cells from the ducts and lobules.7,8

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The only accurate way to diagnose the phyllodes tumor classification is to have the tumor surgically excised. Patients diagnosed with benign and borderline phyllodes tumors are considered cured after local excision.8-10 With such an approach, local recurrence and 5-year survival rates of 4% and 96%, respectively, have been reported for benign phyllodes tumors.7 

Diagnosis and Treatment

A team consisting of a general surgeon, oncologist, primary care provider, and reconstructive plastic surgeon was brought together in consultation for this patient’s mastectomy with a wide excision. The pathology report in this case demonstrated “spindle” cells, which caused greater concern for a malignant process.

The final diagnosis of phyllodes tumor with malignancy was determined with excision of the tumor down to the muscle wall. The literature suggests that a 1-cm negative margin be used in malignant phyllodes tumors.10 Axillary node involvement is rare with malignant phyllodes tumors.9 A positron emission tomography (PET) scan was performed and demonstrated no metastases at the time of surgery. This case was presented at the hospital’s Tumor Board by the oncologist and the plan was to treat after surgical excision with radiation and then chemotherapy.

The American Cancer Society reports that malignant phyllodes are different than other types of breast cancers and are treated more like sarcomas.1 Follow-up is recommended every 6 months for 2 years after treatment and then annually.10 In patients diagnosed with malignancy, chest surveillance with computed tomography (CT) scans should be performed following the guidelines for treatment of sarcomas instead of breast cancers.

Deborah L. Hopla, DNP, APRN-BC, FAANP, FAAN, is an associate professor and director of DNP/MSN/FNP Programs in the Department of Nursing at Francis Marion University in Florence, South Carolina. Dr Hopla is a family nurse practitioner at Hope Health, a federally qualified health care clinic.


  1. The American Cancer Society. Phyllodes tumors of the breast. Accessed August 2, 2022.
  2. Zhang Y, Kleer CG. Phyllodes tumor of the breast: histopathologic features, differential diagnosis, and molecular/genetic updates. Arch Pathol Lab Med. 2016;140(7):665-671. doi:10.5858/arpa.2016-0042-RA
  3. Phyllodes tumors of the breast. The American Society of Breast Surgeons Foundation. Accessed August 2, 2022.
  4. Phyllodes tumor of the breast. Genetic and Rare Diseases Information Center. National Institutes of Health. Accessed August 2, 2022.
  5. Rosen PP. Rosen’s Breast Pathology. 2nd edition. Lippincott William Wikins; 2001.
  6. Limalem F, Kashyap S. Phyllodes tumor of the breast. StatsPearls. StatPearls [Internet]. Updated June 5, 2022. Accessed August 4, 2022.
  7. Mishra SP, Tiwary SK, Mishra M, Khanna AK. Phyllodes tumor of breast: a review article. ISRN Surg. 2013;2013:361469. doi:10.1155/2013/361469
  8. Aydoğan F, Taşçı Y, Sagara Y. Phyllodes tumors of the breast. In: Aydiner A, Igci A, Soran A, eds. Breast Disease: Management and Therapies, Vol 2. 2nd Ed. Springer; 2019;25:365-369. doi:10.1007/978-3-030-16792-9
  9. Tan BY, Acs G, Apple SK, et al. Phyllodes tumours of the breast; a consensus review. Histopathology. 2016; 68(1):5-21. doi:10.1111/his.12876
  10.  Grau AM, Chakravarthy AB. Chug R. Phyllodes of the breast. UpToDate. Accessed August 2, 2022.

This article originally appeared on Clinical Advisor