[Differential diagnosis of invasive ductal carcinoma versus invasive lobular carcinoma of breast].

Objective: To study the diagnostic usefulness of immunohistochemical markers in distinguishing between invasive ductal carcinoma and invasive lobular carcinoma of breast.

Methods: Twenty-four cases of grade I invasive ductal carcinoma, 12 cases of classic invasive lobular carcinoma and 14 cases of invasive carcinoma with mixed ductal and lobular features were retrieved from the archival files of Peking University First Hospital during the period from January, 1998 to December, 2001. Immunohistochemical study for E-cadherin, p120 catenin, epithelia membrane protein 1 (EMP1) and DVL1 was performed.

Results: The positivity rates for E-cadherin in grade I invasive ductal carcinoma and classic invasive lobular carcinoma were 83.3% (20/24) and 0, respectively (P < 0.01). The positivity rates for p120 catenin were 100% in both grade 1 invasive ductal carcinoma (membranous staining) and classic invasive lobular carcinoma (cytoplasmic staining). The positivity rates for EMP1 and DVL1 in gradeI invasive ductal carcinoma were 95.8% (23/24) and 54.2% (13/24), respectively; while those in classic invasive lobular carcinoma were 12 and 5 cases, respectively.

Conclusions: E-cadherin and p120 catenin are useful immunomarkers for distinguishing between invasive ductal carcinoma and invasive lobular carcinoma. On the other hand, EMP1 and DVL1 are of limited value in this respect.