[233] Missed Malignancy in Benign Papillary Lesions of the Breast Diagnosed on Biopsy: Cases with Surgical Follow-Up.

Stephanie Petkiewicz, Shahidul Islam. The Ottawa Hospital, ON, Canada

Background: Papillary lesions are a frequent breast biopsy finding and include intraductal papillomas, papillary lesions with or without atypia and papillary carcinomas. It is controversial whether or not to excise benign papillary lesions diagnosed on biopsy because only a fraction of lesions are later found to contain malignancy. The purpose of this study was to determine the frequency of missed malignancy in papillary breast lesions at our institution and to determine the factors that may have contributed to the missed diagnosis.
Design: A search of hospital pathology records of the past 5 years was performed and benign papillary lesions of the breast with their paired resection specimens were selected for further study. The frequency of malignancy found at final resection was calculated and characteristics of the biopsy that may have contributed to the missed diagnosis of malignancy were sought. The histologic sections from the biopsy and resection specimen were reviewed and examined for possible sources of error.
Results: Of the 39 pairs of biopsy-diagnosed papillary lesions with subsequent resections, 44% of the final resections were found to harbor a malignancy. The most common finding was DCIS, but papillary carcinoma and invasive carcinoma were also diagnosed at resection. The size of the tumor, as determined by radiology, and the method of biopsy did not affect the frequency of occult malignancy. The presence of calcifications seen on imaging was associated with a higher risk of subsequent diagnosis of malignancy. The most common source of error appears to be insufficient sampling of the breast lesion on biopsy with the finding of DCIS on resection that was not present in the biopsy tissue.
Conclusions: Whether or not to excise papillary lesions of the breast continues to be a matter of debate. We have demonstrated that at our institution nearly half the women diagnosed with benign papillary lesions of the breast who go on to surgical resection, will be found to harbor a malignancy. Radiological findings did not predict the discovery of malignancy at resection. Our data indicate that the most common cause for this discrepancy is sampling error with the malignancy not being present within the biopsy material. Due to the high rate of malignancy at resection, our data suggest that women diagnosed with papillary lesions on biopsy should undergo local resection in order to avoid missing a malignancy that may not have been sampled in the biopsy.
Category: Breast

Monday, February 28, 2011 1:00 PM

Poster Session II # 51, Monday Afternoon


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