Case ReportsEvidence for Transformation of Fibroadenoma of the Breast to Malignant Phyllodes TumorHodges, Kurt B. MD*; Abdul-Karim, Fadi W. MD†; Wang, Mingsheng MD*; Lopez-Beltran, Antonio MD‡; Montironi, Rodolfo MD§; Easley, Samantha MD†; Zhang, Shaobo MD*; Wang, Nancy MD†; MacLennan, Gregory T. MD†; Cheng, Liang MD*Author Information *Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN †Department of Pathology, Case Western Reserve University, Cleveland, OH ‡Department of Pathology, Cordoba University, Cordoba, Spain §Institute of Pathological Anatomy and Histopathology, School of Medicine, Polytechnic University of the Marche Region (Ancona), United Hospitals, Ancona, Italy Reprints: Liang Cheng, MD, Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, 350 West 11th Street, Clarian Pathology Laboratory Room 4010, Indianapolis, IN 46202 (e-mail: email@example.com). Received for publication August 4, 2008; accepted November 12, 2008 Applied Immunohistochemistry & Molecular Morphology: July 2009 - Volume 17 - Issue 4 - p 345-350 doi: 10.1097/PAI.0b013e318194d992 Buy Metrics Abstract Fibroadenoma (FA) and phyllodes tumor (PT) of the breast are biphasic tumors composed of variable proportions of epithelial and stromal cells. We identified a case of synchronous FA and PT in the same breast mass. Using laser capture microdissection, loss of heterozygosity analysis was performed on these components to gain potential insight into the histogenetic relationship between FA and PT. Genomic DNA was analyzed at 10 microsatellite loci by polymerase chain reaction. Both tumors showed allelic loss at D7S522. In addition, phylloid tumor showed allelic loss at TP53 and D22S264, not observed in FA. Our data suggest that FA and PT are clonally related and allelic loss at TP53 and D22S264 may be implicated in the progression of FA to phyllode tumor. © 2009 Lippincott Williams & Wilkins, Inc.