doc2016 USCAP Annual Meeting
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2016 USCAP Annual Meeting
2016 USCAP Annual Meeting Breast Pathology Evening Specialty Conference Xiaoxian (Bill) Li, MD PhD Department of Pathology and Laboratory Medicine Emory University Disclosure • Dr. Li has nothing to Disclose 42 yo female with a 1.8 cm mass in the left breast Differential diagnosis • Malignant phyllodes tumor with liposarcomatous component • Metaplastic carcinoma • Fibroadenoma • Benign or borderline phyllodes tumor Differential diagnosis • Malignant phyllodes tumor with liposarcomatous component: – True well differentiated liposarcoma (WDL) of the breast is exceedingly rare. – If WDL present, usually a component of malignant phyllodes tumor. – Expansile growth pattern and the atypical cells are not predominantly seen in the peri-lobular stroma. – Could be positive for MDM2 amplification (needs more studies). MDM2 negative, Red=MDM2, Green=SE12 centromere for 12 Differential diagnosis • Metaplastic carcinoma: – Usually associated with high grade recognizable invasive or in situ carcinoma. – Obvious malignant features including high mitotic rate, atypical mitosis and necrosis. – Positive for CK, HMWCK, p63 staining AE1/AE3 Ki-67 Differential diagnosis • Fibroadenoma • Benign or borderline phyllodes tumor Fibroepithelial Tumors • Biphasic proliferation of stromal and epithelial components • Generally classified into fibroadenoma and phyllodes tumor Histological Features Fibroadenoma Benign PT Borderline PT Stromal cellularity Mild to moderate, Uniform Mild to moderate, Can be nonuniform Moderate, Can be non-uniform Marked Stromal atypia None Mild Moderate Marked Mitosis None to very low <5/10HPF 5-9/10HPF >=10/10HPF Stromal overgrowth None None None to very focal Present Malignant heterologous None None None May be present Margins Well-defined Well-defined Focally permeative Permeative Adopted from WHO classification of breast tumors, 2012 Malignant PT The morphology has NOT changed for 37 years Fibroadenoma with stromal giant cells with atypical mitosis Lei and Gilcrease, 2009, Ann Diago Pathol The stromal giant cells are benign reactive stromal cells • When present with carcinoma, the stromal giant cells are generally separate from carcinoma. • None of the reported benign fibroepithelial lesions with stromal giant cells recurred at follow up. • The stromal giant cells are generally mitotic inactive as surrounding stromal cells. Left breast, mammotome core biopsy: - Fibroepithelial tumor with stromal giant cells, favoring fibroadenoma. Follow up Lumpectomy was performed about a month later… Well circumscribed margin Biopsy site Left breast, lumpectomy: - Fibroadenoma with stromal giant cells - No recurreance after 1 year follow up Here is another one… AE1/AE3 Take Home Messages • Be aware of stromal giant cells in breast. • Presence of stromal giant cells should NOT change the diagnosis or grading of fibroepithelial tumors. Acknowledgement • Dr. William McNeil from the Dekalb Medical Center for sending me the cases and blocks.
