Discrepancies in the diagnosis of intraductal proliferative lesions of the breast and its management implications: results of a multinational survey

Abstract

To measure discrepancies in diagnoses and recommendations impacting management of proliferative lesions of the breast, a questionnaire of five problem scenarios was distributed among over 300 practicing pathologists. Of the 230 respondents, 56.5% considered a partial cribriform proliferation within a duct adjacent to unequivocal ductal carcinoma in situ (DCIS) as atypical ductal hyperplasia (ADH), 37.7% of whom recommended reexcision if it were at a resection margin. Of the 43.5% who diagnosed the partially involved duct as DCIS, 28.0% would not recommend reexcision if the lesion were at a margin. When only five ducts had a partial cribriform proliferation, 35.7% considered it as DCIS, while if >or=20 ducts were so involved, this figure rose to 60.4%. When one duct with a complete cribriform pattern measured 0.5, 1.5, or 4 mm, a diagnosis of DCIS was made by 22.6, 31.3, and 94.8%, respectively. When multiple ducts with flat epithelial atypia were at a margin, 20.9% recommended reexcision. Much of these discrepancies arise from the artificial separation of ADH and low-grade DCIS and emphasize the need for combining these two under the umbrella designation of ductal intraepithelial neoplasia grade 1 (DIN 1) to diminish the impact of different terminologies applied to biologically similar lesions.

Fig. 1

The first scenario assessed how pathologists would diagnose a partially involved duct adjacent to unequivocal cribriform DCIS, and whether they would recommend reexcision if it were less than 0.1 mm from a resection margin

Fig. 2

In question 2, participants were asked whether the number of partially involved ducts affects their decision to make a diagnosis of ADH

Fig. 3

Responses to question 3 demonstrated what pathologists thought was the lowest size threshold required to make a diagnosis of DCIS

Fig. 4

Question 4 evaluated how participants would manage flat epithelial atypia close to a resection margin

Fig. 5

Question 5 surveyed how pathologists measured invasive carcinoma in the presence of multifocal microinvasion