[348] Fibroepithelial Lesion with Cellular Stroma: Topoisomerase 2 Is a Helpful Marker To Differentiate Fibroadenoma from Phyllodes Tumor on Needle Core Biopsy

S Zhang, J Kasznica, R Chandrasekhar, G Wilding, T Khoury. Roswell Park Cancer Institute, Buffalo, NY

Background: The differential diagnosis of fibroepithelial lesions with cellular stroma (FELCS) in core needle biopsy (CNB) specimens ranges from fibroadenoma (FA) to phyllodes tumor (PT). The management of these two lesions is different. We intended to explore possible morphologic and immunohistochemical (IHC) parameters that may predict the final diagnosis on the excisional biopsy.
Design: A series of FELCS cases diagnosed on CNB with matching excisional biopsy were retrieved from our files between 2003 and 2009. The following histologic parameters were recorded: stromal cellularity (1, 2, or 3), stromal cell atypia (1, 2, or 3), stromal cell mitosis per ten high power fields, stroma overgrowth, infiltrative edge, stromal cellularity enhanced at epithelium and leaf-like pattern. Patients' age and tumor size were also recorded. The following IHC stains were performed on CNB: KI-67 (clone MIB-1), p53 (clone DO7) and Topoisomerase 2 (TOPO2) (clone EP1054Y). Percentage of positive cells was recorded. Fisher's exact test and Wilcoxon non-parametric test were used for statistical analyses.
Results: The table below illustrates all the findings.

Histologic, Clinical and IHC Finding
FA (n=8)PT (n=12)p value
Age (y), median (range)42 (35-48)47 (30-82)NS
Size (cm), median (range)1.35 (0.5-2.5)3.45 (0.5-15)0.022
Stromal cellularity
1 or 27 (87.5)*8 (66.7)NS
31 (12.5)4 (33.3)NS
Stromal cell atypia
16 (75.0)5 (41.7)NS
2 or 32 (25.0)7 (58.3)NS
Stromal cell mitosis
No6 (75.0)8 (66.7)NS
Yes2 (25.0)4 (33.3)NS
Stromal overgrowth
No5 (62.5)6 (50.0)NS
Yes3 (37.5)6 (50.0)NS
Infiltrative edge**
No8 (100.0)6 (66.7)NS
Yes0 (0.0)3 (33.3)NS
Stromal cellularity enhanced at epithelium
No8 (100.0)11 (91.7)NS
Yes0 (0.0)1 (8.3)NS
Leaf-like pattern
No6 (75.0)5 (41.7)NS
Yes2 (25.0)7 (58.3)NS
Median (range ) Ki-67 (%)5 (0-20)10 (1-50)NS
Median (range ) p53 (%)2.5 (0-90)20 (0-80)NS
Median (range ) TOPO2 (%)0 (0-2)2 (0-10)0.037
* No. (%), ** n=9 for PT

Conclusions: Larger clinically measured tumor size and presence of Topoisomerase 2 staining can predict PT on CNB.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 40, Wednesday Morning


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