Background: There is currently debate as to whether all papillary lesions diagnosed on breast needle core biopsy require surgical excision. The recent development of large volume “mammotome” biopsy offers a means of non-operative removal. There is little published data regarding the success of this approach.
Aim: To review the pathological and radiological findings in cases of non-diagnostic “B3” and “B4” papillary lesions identified on conventional breast needle core biopsy with a view to assessing the usefulness of mammotome biopsy as a means of avoiding diagnostic surgery.
Methods: All breast core biopsies containing a “B3” or “B4” papillary lesion between 23/06/05 and 14/08/07 were identified by searching the pathology department computer records. Follow up histology was identified from pathology department computer records and radiological details were obtained from the local screening unit or the radiology department.
Results: Thirty-four papillary breast core biopsies were included in this study. Twenty-one were from screen-detected lesions and thirteen were from patients presenting symptomatically. Thirty-one were classified “B3” and three were “B4s”. Four cases included an atypical ductal epithelial proliferation (all “B4”s and one “B3”).Fourteen patients underwent open surgical biopsy, fifteen mammotome excision and five had no subsequent procedure. All fifteen cases who underwent mammotome biopsy did not show atypia on the core and thirteen (87%) proved benign. In two cases the mammotome biopsy was either atypical or malignant prompting surgery at this point. In both cases the mammotome biopsy changes derived from areas of ductal carcinoma in situ (DCIS) arising in the context of multiple intraduct papillomas and both were distinctive mammographically in presenting with large areas of segmental calcification. Eleven of the fourteen cases undergoing surgical excision did not show atypia on the core and all proved benign. All three with atypia on the core proved malignant.
Conclusion: In selected cases, large volume (“mammotome”) biopsy may improve sampling of papillary lesions such that malignancy may be excluded without recourse to diagnostic surgery. The presence of an atypical papillary proliferation on core or mammotome biopsy is a strong predictor of malignancy. This has important implications for both symptomatic and breast screening services.