Phyllodes tumors (from Greek: phullon), are a rare type of biphasic fibroepithelial mass that form from the periductal stromal and epithelial cells of the breast.

[3] Phullon, which means 'leaf' in Greek, describes the unique papillary projections characteristic of phyllodes tumors on histology.

[1] Diagnosis is made via a core-needle biopsy and treatment is typically surgical resection with wide margins (>1 cm), due to their propensity to recur.

[3] In addition, larger masses can stretch the overlying breast tissue leading to nipple retraction, chest wall fixation, and in advanced cases, ulceration from pressure necrosis.

[9] In the Wnt pathway, gene transcription via B-catenin is a highly regulated process by proteins including, but not limited to, c-myc, c-jun, Fra, and cyclin D1.

[11] Despite their propensity to grow rapidly and deform the overlying breast tissue, approximately 20% of phyllodes tumors can present as a nonpalpable mass on screening mammography.

[13] Phyllodes tumors can only be diagnosed histologically, as they tend to have many overlapping features with other breast masses on physical examination and radiological imaging.

[8] This term incorporates a spectrum of diseases ranging from a benign fibroadenoma to a malignant phyllodes tumor, with numerous variants in between.

[14] Phyllodes tumors may be considered benign, borderline, or malignant depending upon their histological features, including stromal cellularity, infiltration of the epithelial-stromal interface, and mitotic activity.

[15] A large case series from the MD Anderson Cancer Center reported the incidence of each type of phyllodes tumor as benign (58%), borderline (12%), and malignant (30%).

[20] Patients who have not had a mastectomy should continue regular breast cancer screening based on the recommendations by the United States Preventative Services Task Force.

[23] Radiation treatment, after breast-conserving surgery with negative margins, may significantly reduce the local recurrence rate for borderline and malignant tumors.