Cytologically Yours: Unknowns: 201312: Case 3

Clinical History

54 year old female. Left breast 1cm nodule. FNA.

Cytology

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Resident Questions

• Diagnosis?

• Cytology diagnosis: Proliferative lesion, consistent with fibroadenoma.
• Surgical diagnosis: Fibroadenoma

Surgical Pathology

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Cytologic Features

• Biphasic appearance: Epithelium and mesenchymal/stromal
• Epithelium appears as cohesive monolayer sheets of well-organized epithelium with branching and papillary-like architecture (staghorn) or tubular
• Naked bipolar myoepithelial cells in the background (rice grain appearance)
• Variably cellular stromal fragments