BREAST CYTOPATHOLOGY

Technical Aspects 5
In the case of lesions such as abscesses and cysts, FNA can
be a diagnostic and treatment tool. It can be used to obtain
material for special studies such immunocytochemistry and
molecular analysis.
The contraindications to breast FNA are almost nonexistent.
The complication rate is generally quite low and the
complications themselves minor. Pain, especially in the subareolar
area, is reported, and rarely pneumothorax has
occurred. Needle tract seeding is quite uncommon. Other
more problematic complications include hemorrhage (bleeding/hematoma),
infection, and vasovagal reaction. Displacement
of epithelial cells or necrosis occurring during the
FNA procedure can distort the aspirate or the subsequent
excision and can mimic invasion of carcinoma on the final
surgical excision.
Fat, stroma, and functional epithelial units containing
ducts, ductules, and acini characterize the normal histology
of the adult breast. A cytology specimen normally consists of
fat, fibrous tissue, stromal cells, and few duct or acinar cells.
These epithelial cells should be regularly shaped and arranged
in honeycombed sheets. Round to oval myoepithelial cells
may be present but may not be obvious (Figures 1.1 and 1.2).
More glands are seen in the lactating than nonlactating female
breast, and these cells have large nuclei, large nucleoli, and
vacuolated cytoplasm. Breast tissue is subject to hormonal
effects, such as benign secretory change. These changes, if not
recognized as such, can be mistaken for atypia in breast FNA
samples.
Adequacy of an aspiration is somewhat laboratory
and operator dependent. If a lesion regresses after aspiration
or yields only fat when a lipoma is suspected, it may be
deemed adequate even if it is paucicellular. In general, more
cells are required to make a benign diagnosis than a malignant
one. Our laboratory uses the criteria of six clusters of
epithelial cells (about 15 cells per cluster) spread over two
glass slides. If the laboratory adheres to strict adequacy
requirement, the number of false-negative diagnoses will
decrease, but the number of unsatisfactory specimens will
increase.