Classification of Fibroepithelial Lesions of the Breast in Core Needle Biopsy With Implications for Further Management
Emad A. Rakha, Cecily Quinn, Wendy A. Raymond, Kimberly H. Allison, Sunil Badve, Edi Brogi, Grace Callagy, Emmanuelle Charafe‐Jauffret, Chih‐Jung Chen, Yunn‐Yi Chen, Laura C. Collins, Gábor Cserni, Lounes Djerroudi, Shabnam Jaffer, Maria Pia Foschini, Helenice Gobbi, Mihir Gudi, Oi Harada, Janina Kulka, Hajime Kuroda, Sunil R. Lakhani, Xiaoxian Li, Takuya Moriya, Sandra O’Toole, Sarah E. Pinder, Elena Provenzano, Ayşegül A. Şahin, Fernando Schmitt, Abeer M. Shaaban, Kalliopi P. Siziopikou, Ping Tang, Gary M. Tse, Zsuzsanna Varga, Anne Vincent‐Salomon, Hannah Y. Wen, Rin Yamaguchi, Wentao Yang, Stephen B. Fox, Stuart J. Schnitt, Ian O. Ellis, Puay Hoon Tan
Abstract
Fibroepithelial lesions (FELs) of the breast represent a diverse group of biphasic tumors with varying morphologies and clinical behavior. The classification of FELs is mainly based on a constellation of diagnostic criteria, and intralesional heterogeneity is not uncommon. Therefore, reporting FELs in a core needle biopsy (CNB) with limited tissue material can be challenging as not all the features may be represented for assessment. Differentiating a classic fibroadenoma from a well-sampled phyllodes tumor (PT) is generally straightforward. However, cellular fibroadenoma, morphologically heterogeneous benign PT, and myoid hamartoma can overlap histologically. Accurate grading of PT is also challenging on CNB and carries significant management implications. In this article, we provide an overview and propose a pragmatic approach to reporting FELs on CNB, particularly for lesions with overlapping features. Guidance using the UK/European "B" classification of FELs alongside descriptive reporting of the various lesions, is also presented to aid in management decisions.