"Leaf-like” fibroepithelial tumors, theorized to develop from transformation of fibroadenomas (controversial); >50% are benign, 25% are malignant

Epidemiology: Accounts for 0.5% of all breast cancers; Incidence ~2 per 1 million women. Average age at diagnosis: mid-40s. Metastasis (most commonly to lungs) occurs in 13-40% of cases with poor prognosis. Associated with Li-Fraumeni syndrome

Clinical presentation: Mass on physical exam (80%) or mammographic abnormality (20%); Physical exam: Large (4-8cm at detection), firm, mobile mass +/- shiny/stretched/ulcerated skin over mass; Breast pain may be more common with Phyllodes tumors compared to fibroadenomas

Diagnosis: Core needle biopsy (high false negative rate) or excisional biopsy; Increased stromal celluarity differentiates Phyllodes from fibroadenoma

Imaging features

–     Ultrasound: Clefts or round cysts within solid, circumscribed mass

–     Mammogram: Smooth, polylobulated mass resembling a fibroadenoma

Treatment: Wide local excision with large negative margins (1cm), adjuvant radiation therapy for borderline/malignant tumors to reduce recurrence risk, adjuvant chemotherapy for sarcoma (will not respond to standard chemotherapeutics for IDC) reserved for high-grade malignant/large recurrent tumors (>5cm). Recurrence rate is high (8% - benign, 21-36% - borderline/malignant); Usually involves lungs and occurs within 2 years of excision; Surveillance CXR + breast exam Q6mos x 2yrs then annually

(Grau 2014, Wiratkapun 2014)

MALIGNANT BREAST DISORDERS:

Phylloides Tumor