Papillary breast lesions in fine-needle aspiration biopsy specimens
Emily E. Volk, MD
Diagnosing papillary lesions of the breast using fine-needle aspiration biopsy, or FNAB, is a notorious challenge. The published diagnostic criteria needed to distinguish benign papillomas from true papillary malignancy are not particularly reliable or reproducible.
National Cancer Institute guidelines (Abati A, et al. Acta Cytol. 1996; 40: 1120-1126) for breast FNAB recommend that all papillary lesions be placed in an indeterminate category to avoid the potential false-positive or false-negative diagnoses associated with these lesions. Further, the criteria to assist in distinguishing benign papillomas from benign nonpapillary lesions, such as fibroadenoma and proliferative fibrocystic changes, have not been widely scrutinized. Potential exists for nonpapillary lesions to be misidentified on FNAB as papillary, thus subjecting patients to unnecessary surgical excision of these pseudopapillary lesions.
Aylin Simsir, MD, and colleagues produced a noteworthy review of breast lesions diagnosed as papillary by FNAB (Cancer. 2003; 99: 156- 165). The authors reviewed smears from 70 FNAB diagnosed as papillary lesions and correlated the cytology with the surgical pathology of the excised specimens. Their first objective was to determine the accuracy of FNAB diagnosis of papillary lesions in differentiating true papillary from nonpapillary proliferation such as is seen in benign fibrocystic change. Their second objective was to evaluate cytological criteria to distinguish benign papillomas from true papillary malignancies.
The authors provide useful clues to help distinguish papillary from nonpapillary lesions. They also provide diagnostic clues for papillary malignancy. The authors caution against an overly aggressive approach to diagnosing papillary malignancy because, for instance, a benign infarcted papilloma may closely mimic a malignancy on FNAB. They recommend classifying these lesions as benign or atypical, as suggested by the NCI.
The authors offer a list of cytological features that helps to more accurately distinguish true papillary lesions from pseudopapillary lesions, as well as a list of features that may indicate malignancy. This allows pathologists to more accurately distinguish patients whose lesions require further surgical intervention from those whose lesions do not.
Dr. Volk, a member of the CAP Cytopathology Committee, is staff pathologist at William Beaumont Hospital, Troy, Mich.