Diagnostic Uncertainty of Fibroepithelial Lesions on Core Biopsy Results in Increased Likelihood of Excision and Final Diagnosis of Phyllodes Tumor
Stephanie JT Chen, Judy C Pang, Lili Zhao, Julie M Jorns. University of Michigan, Ann Arbor, MI
Background: Fibroepithelial lesion (FEL) is a broad term encompassing fibroadenoma (FA) and phyllodes tumor (PT). FA and PT are treated differently but can have overlapping histologic features, making diagnosis challenging on core biopsy. The designation of FEL may be used when there is diagnostic uncertainty. Study aims were to examine the frequency and significance of core biopsy diagnosis (CBD) of FELs and investigate which features may better predict PT vs. FA.
Design: An electronic database query (1/07-1/12) identified patients with CBD of FEL (N=603). Cases were separated into 4 groups: 1) FA (N=573); 2) FEL, favor FA (N=19); 3) FEL, favor PT (N=10) and 4) PT (N=1). In excised cases, biopsy and excision diagnoses were compared and clinicopathologic features assessed. Core biopsies from cases with follow-up excision were blindly reviewed by 2 breast pathologists for overall favored diagnosis and histologic features (based on a scoring system for architecture, cellularity, stromal atypia and stromal mitoses).
Results: Of cases with known follow-up 45/573 (7.9%) FA and 29/29 (100%) group 2-4 cases were later excised. Biopsy-excision correlation is shown in Table 1. Of note, 1 group 3 patient had excision elsewhere with unknown results.
|1) FA||44 (97.8%)||1 (2.2%)|
|2) FEL, favor FA||13 (72.2%)||5 (27.8%)|
|3) FEL, favor PT||4 (45.4%)||5 (55.6%)|
|4) PT||0||1 (100%)|