Xi Wang
University of Rochester Medical Center, USA
Title: Breast metaplastic spindle cell carcinoma and its mimics: An update through the discussion on real cases
Biography
Biography: Xi Wang
Abstract
Metaplastic carcinoma is the malignant neoplasm that exhibits microscopic structural changes, which diverge from glandular differentiation. It is a heterogeneous group of tumors. The 2012 WHO classification based on the descriptive morphology has divided it into several different sub-groups, among which, spindle cell carcinoma (including fibromatosis-like metaplastic carcinoma) represents the most diagnostic challenge to pathologists, especially on core biopsies. Many breast lesions/tumors could present, at least focally, as spindle cell morphology. However, their clinical significance is greatly different, which makes the differential diagnosis very critical. The spectrum could at one end consist of hypertrophic scar/pseudoangiomatous stromal hyperplasia/nodular fascitis, the lesions mostly considered as a reactive/repair process, while the other end malignant phyllodes tumor/malignant adenomyoepithelioma/mesenchymal sarcomas. Previous malignant myoepithelioma carcinoma is now believed to be part of the spindle cell carcinoma. The morphological overlapping among these lesions sometimes could be overwhelming. A panel of markers for immunohistochemical stain is recommended, but they may not always be helpful. This presentation will use five real cases to discuss the detailed morphological features and immunohistochemical patterns of metaplastic spindle cell carcinoma and its mimics, including the key points for differential diagnoses.