Phyllodes Tumors: Histologic Features in Relation to Clinical Follow-Up
Monica R Phillips, Yassi Omidvar, Sophia K Apple. UCLA, Los Angeles, CA
Background: Phyllodes tumors (PTs) are rare fibroepithelial neoplasms of the breast which are subdivided into benign, borderline and malignant based on histologic criteria. Surgical excision with a wide margin (>1cm) is the standard treatment to minimize recurrence, however, the histologic classification of PTs does not reliably predict clinical behavior despite adequate excision. This study aims to examine the clinicopathologic features and outcome of PTs in order to identify risk factors for local recurrence and distant metastasis.
Design: A retrospective review of 62 patients with PTs from 1996-2012 was analyzed with regard to histologic features and clinical follow-up. We included only patient samples with slides available for review and excluded all cases that had no or loss of clinical follow-up. Analysis of histologic features included tumor size, mitotic rate/10 HPF, stromal overgrowth, periglandular cuffing, cellularity, necrosis, heterogeneous differentiation, borders, margin width and co-existing fibroadenoma (FA). Clinical features included age, follow-up duration, type of surgery, local recurrence, distant metastasis and death rate.
Results: Benign, borderline and malignant PTs comprised 31/62 (50%), 14/62 (23%) and 17/62 (27%) with mean age of 38, 44 and 50 years, respectively. Median follow-up was 54 months.
|Benign PT||Borderline PT||Malignant PT|
|Mean Age (yr)||38||44||50|
|Mean size (cm)||3.1||4.8||6.7|
|Avg mitoses/10 HPF||1||5||17|
|Stromal overgrowth||16% focal||43% focal||88% diffuse|
|Local excision vs mastectomy||0% vs 100%||86% vs 14%||47% vs 53%|
|Margin: recurrence rate|
|@: 4/9 (44%)||1/4 (25%) pushing||3/14 (14%)||0|
|<1mm: 3/9 (33%)||1/4 (25%) pushing||0||2/3 (67%)|
|2mm: 1/9 (11%)||1/4 (25%) irreg pushing||0||0|
|neg (>1cm): 3/9 (33%)||1/4 (25%) pushing||2/10 (20%)||0|