Anatomic Pathology / PAPILLOMAS AND ATYPICAL PAPILLOMAS IN BREAST CORE NEEDLE BIOPSY SPECIMENS Papillomas and Atypical Papillomas in Breast Core Needle Biopsy Specimens Risk of Carcinoma in Subsequent Excision

We sought to define the risk associated with papillomas and atypical papillomas in breast core needle biopsy specimens from a series of approximately 8,500 biopsies performed during 8 years. From a total of 62 papillary lesions (including papillomas and atypical papillomas), 40 (65%) had histologic followup. Overall, 15 (38%) of 40 patients had ductal carcinoma in situ (12 cases) or invasive carcinoma at excision (3 cases). Eight cases diagnosed as papilloma had benign follow-up. Slides were available for review in 38 cases and reclassified into benign papilloma with florid hyperplasia and no or minimal atypia (18 cases), papilloma with separate foci of atypical ductal hyperplasia (7 cases), and severely atypical papillomas “suspicious” for papillary carcinoma (13 cases). Carcinoma was identified in 0 (0%), 2 (29%), and 12 (92%) cases, respectively. We conclude that while atypical papillary lesions and papillomas with associated atypical ductal hyperplasia in breast core needle biopsy specimens are associated with a risk of carcinoma, lesions diagnosed as papilloma or papilloma with no or minimal atypia are benign and do not need to be excised. Core needle biopsy of the breast is being used increasingly to define radiologically and clinically identified lesions. There is abundant evidence that atypical papillary lesions, consisting of papillomas with atypia or atypical ductal hyperplasia, are associated with a significant risk of carcinoma and need to be excised.1-7 However, the significance of a diagnosis of papilloma in these specimens is controversial. Only a few small series exist,1-6 but taken together these series suggest a small risk of carcinoma. As a result of this uncertainty, a recent influential review8 suggested that “there is a small but definite chance of atypia or malignancy on excision,” and “until more data become available it may be most prudent to recommend excision for all papillary lesions, even those with completely benign features on core needle biopsy.” As a result of this, we began recommending excision for all papillary lesions. Since then it has been our impression that papillomas are not associated with an increased risk of carcinoma. To further investigate this, we reviewed our experience with papillary lesions in breast core needle biopsy specimens. Materials and Methods The results of breast core needle biopsy specimens interpreted from August 20, 1996, to November 1, 2003, at Baptist Hospital of Miami, Miami, FL, were reviewed. All biopsy specimens with a diagnosis of a papillary lesion were identified. Cases originally were classified as papilloma or atypical papillomas. Atypical papillomas included papillomas with atypical features or papillomas with coexistent atypical Am J Clin Pathol 2004;122:217-221 217 217 DOI: 10.1309/K1BNJXETEY3H06UL 217 © American Society for Clinical Pathology Renshaw et al / PAPILLOMAS AND ATYPICAL PAPILLOMAS IN BREAST CORE NEEDLE BIOPSY SPECIMENS ductal hyperplasia, as previously defined.9 On review, cases were reclassified into 1 of 3 categories: benign papillomas with no or minimal atypia ❚Image 1❚, benign papillomas with adjacent atypical ductal hyperplasia ❚Image 2❚, and severely atypical papillomas ❚Image 3❚. Severely atypical papillomas had features suggestive of papillary carcinoma. Criteria for this diagnosis are based on the previously outlined criteria10 and include the presence of hyperchromatic nuclei, marked nuclear atypia, cribriform pattern, absent supporting stroma, and a monotonous cell population. In general, however, the cells resembled those of intermediate-grade ductal carcinoma in situ, solid or cribriform type, and included a solid or cribriform architecture without streaming or else resembled those of papillary carcinoma and consisted of sheets of somewhat elongated, hyperchromatic, and atypical cells or multiple layers of elongated cells covering papillary fronds. Benign papillomas with adjacent atypical ductal hyperplasia had areas that qualified as atypical ductal hyperplasia as previously defined.9 All other papillary lesions were placed in the category of benign papilloma with no or minimal atypia. All breast core needle biopsy specimens were obtained by clinicians; more than 95% were performed by radiologists and consisted almost exclusively of 11and 14-gauge core needle biopsy specimens performed under ultrasound or stereotactic guidance. All specimens were received fixed and were processed routinely. Up to 5 cores were processed in a single block; if more than 5 cores were present, an additional block was prepared. Each block was sectioned entirely to produce 8 slides and between 2 and 5 levels per slide. All diagnoses 218 Am J Clin Pathol 2004;122:217-221 218 DOI: 10.1309/K1BNJXETEY3H06UL © American Society for Clinical Pathology A B