The clinical behavior of mixed ductal/lobular carcinoma of the breast: a clinicopathologic analysis

Abstract

Background: To date, the clinical presentation and prognosis of mixed ductal/lobular mammary carcinomas has not been well studied, and little is known about the outcome of this entity. Thus, best management practices remain undetermined due to a dearth of knowledge on this topic.

Methods: In this paper, we present a clinicopathologic analysis of patients at our institution with this entity and compare them to age-matched controls with purely invasive ductal carcinoma (IDC) and historical data from patients with purely lobular carcinoma and also stain-available tumor specimens for E-cadherin. We have obtained 100 cases of ductal and 50 cases of mixed ductal/lobular breast carcinoma.

Results: Clinically, the behavior of mixed ductal/lobular tumors seemed to demonstrate some important differences from their ductal counterparts, particularly a lower rate of metastatic spread but with a much higher rate of second primary breast cancers.

Conclusions: Our data suggests that mixed ductal/lobular carcinomas are a distinct clinicopathologic entity incorporating some features of both lobular and ductal carcinomas and representing a pleomorphic variant of IDC.

Figure 1

H&E of a mixed ductal/lobular tumor. 200× magnification of an H/E stained section of mixed ductal/lobular histology tumor. Ductal histology is noted.

Figure 2

H&E of a mixed ductal/lobular tumor. 200× magnification of an H/E stained section of mixed ductal/lobular histology tumor. Lobular histology is noted.

Figure 3

E-cadherin immunostaining of the ductal components of the tumor. E-cadherin staining on the same specimen displays the presence of E-cadherin in the ductal areas of the tumor.

Figure 4

E-cadherin immunostaining of the lobular components of the tumor. E-cadherin staining on the same specimen displays the presence of E-cadherin in the lobular component of the tumor, suggesting that this mixed ductal/lobular tumor is indeed a variant of pleomorphic ductal carcinoma.

Figure 5

Overall Survival. Kaplan-Meier plot of overall survival of patients with mixed ductal/lobular histology tumors and patients with purely invasive ductal carcinomas reveals no significant difference between the two groups.

Figure 6

Disease-Free Survival. Kaplan-Meier plot of disease-free survival of patients with mixed ductal/lobular histology tumors and patients with purely invasive ductal carcinomas reveals no significant between the two groups as well.