FNA of breast Slide session The 6 th

FNA of breast Slide session The 6 th Arab-British School of Pathology Nina S Shabb AUBMC

Fibroepithelial lesions Cases 1 -3 o o o Fibroadenoma 3 components Phyllodes tumor vs FA n Older women n Larger/cystic n Adequate sampling n Cellular stromal fragments n Cytologic atypia/mitosis (malignant) Epithelial discohesion and atypia? Adenocarcinoma arising in FA PT misdiagnosed as adenocarcinoma (proper preparation)

Fibroadenoma o o o Most common cause of false positive dx Cellular smear, may find single cells with atypia and discohesion Do not spend too much time on high power looking for discohesive single cells. Helpful feature: Numerous ME cells Do not call malignant with numerous ME cells in background

Final dx o Case 1: n n o Case 2: n n o FNA dx: Cellular FA vs Benign PT. Final dx: FA FNA dx: Cellular FA vs Benign PT. Final dx: PT Case 3: n n PT/C 4 (low grade carcinoma) Final dx: PT

Ductal adenocarcinoma NOS Cases 4 and 5 o Cytologic features? n n n o Tumor cellularity Discohesion Single cells with features of malignancy Grading n Nuclear grade 1 -3

Final dx o Case 4: n n o FNA dx: Adenoca NG 2/3 Final DX: Adenoca nos Grade 2/3 Case 5 n n n FNA dx: Adenoca NG 1/3 Final DX: Adenoca nos Grade 1/3

Mucinous/colloid carcinoma Cases 6 and 7 o o o Gross can mimic benign disease. Mucin seen grossly while aspirating and smearing Extracellular mucin on pap and DQ Round balls of low grade tumor cells If pure mucinous, has better prognosis but FNA can not determine that. FNA: Suggestive of mucinous ca

Lobular carcinoma Case 8 and 9 o What are the FNA features of classic lobular carcinoma?

Case 8 o Classic lobular carcinoma

Case 9 o o o Pleomorphic lobular ca Intraductal papilloma How do we deal with papillary lesions on FNA?

Tubular ca Case 10 o o o Angular, rigid, bent tubular clusters, sharp borders Crowded nuclei Minimal tumor discohesion Dispersed single cells, minimal atypia Absence/paucity of ME cells Peripheral perpendicular cells

FNA of axillary LN Case 11 o o o Metastatic adenocarcinoma c/w breast primary False negative? Other malignancy?

FNA of DCIS Case 12 o DCIS Grade 3: n n o DCIS cribriform n n o Pleomorphic carcinoma cells, calcium, necrosis, macrophages casting Calcification on mammogram Low grade carcinoma punched out holes in cell clusters DCIS grades 1 and 2: n No distinguishing features