FNA of breast Slide session

The 6th Arab-British School of Pathology

Nina S ShabbAUBMC

Fibroepithelial lesionsCases 1-3 Fibroadenoma 3 components Phyllodes tumor vs FA

Older women Larger/cystic Adequate sampling Cellular stromal fragments Cytologic atypia/mitosis (malignant)

Epithelial discohesion and atypia? Adenocarcinoma arising in FA PT misdiagnosed as adenocarcinoma (proper preparation)

Fibroadenoma 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 Case 1:

FNA dx: Cellular FA vs Benign PT. Final dx: FA

Case 2: FNA dx: Cellular FA vs Benign PT. Final dx: PT

Case 3: PT/C4 (low grade carcinoma) Final dx: PT

Ductal adenocarcinoma NOSCases 4 and 5

Cytologic features? Tumor cellularity Discohesion Single cells with features of malignancy

Grading Nuclear grade 1-3

Final dx

Case 4: FNA dx: Adenoca NG 2/3 Final DX: Adenoca nos Grade 2/3

Case 5 FNA dx: Adenoca NG 1/3 Final DX: Adenoca nos Grade 1/3

Mucinous/colloid carcinomaCases 6 and 7

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 carcinomaCase 8 and 9

What are the FNA features of classic lobular carcinoma?

Case 8

Classic lobular carcinoma

Case 9

Pleomorphic lobular ca Intraductal papilloma How do we deal with papillary lesions

on FNA?

Tubular caCase 10

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 LNCase 11

Metastatic adenocarcinoma c/w breast primary

False negative? Other malignancy?

FNA of DCISCase 12

DCIS Grade 3: Pleomorphic carcinoma cells, calcium,

necrosis, macrophages casting Calcification on mammogram

DCIS cribriform Low grade carcinoma punched out holes in cell clusters

DCIS grades 1 and 2: No distinguishing features