Case: The patient is a 71 year-old woman who presented with enlarging painful breast mass. She had history of previous excision of a fibroadenoma in her left breast in 1993. She underwent menopause at 52 and does not take estrogen. Diagnostic imaging revealed 4.7cm breast mass, which had increased from prior measurement of 2.8cm to 4.7cm. Core biopsy demonstrated a fibroepithelial neoplasm areas of hypercellular stroma and occasional stromal mitotic figures most consistent with phyllodes tumor. Lumpectomy was performed. Final pathology showed a 4.8cm well-demarcated tumor with mildly pleomorphic spindled cells in the stroma and up to 1 per 10 mitoses per high powered field, consistent with benign phyllodes. The patient was followed every 6 months with imaging for 2 years without recurrence.
Conclusions:
Phyllodes tumors are rare fibroepithelial tumors of varying metastatic potential that can be mistaken for benign fibroadenomas. Phyllodes tumors should be surgically excised with wide margins, needing radiation or chemotherapy only if recurrent or large (>10cm), whereas fibroadenomas can be managed expectantly if asymptomatic (Gnerlich, 2014). Phyllodes tumors are often diagnosed in women ages 35-55. The patient in this case was diagnosed at a more advanced age with benign disease, although older age is more often associated with increased histologic grade (Mishra, 2013) (Karim, 2009). Borderline and malignant tumors are more likely to recur within two years of resection; there is less data on recurrence rates of benign tumors.
Clinical Significance:
Phyllodes tumors should be suspected with rapid growth of a known fibroadenoma. Core biopsy should be performed rather than fine needle aspiration for accurate diagnosis. Although phyllodes tumors comprise less than 1% of all breast neoplasms, it is crucial that uncommon pathologies are diagnosed correctly so that patients receive appropriate treatment
