Interobserver variability and aberrant E-cadherin immunostaining of lobular neoplasia and infiltrating lobular carcinoma

Abstract

The distinction between lobular neoplasia and infiltrating lobular carcinoma from ductal neoplasia and infiltrating duct carcinoma with equivocal histologic features may present a challenge as this distinction has important therapeutic implications. Although E-cadherin staining has been of value in helping to make this determination, the variability of the E-cadherin staining pattern and the immunohistochemistry techniques can be problematic in clinical practice. A total of 161 cases of breast lesions previously diagnosed as lobular neoplasia and infiltrating lobular carcinoma were selected from the departmental files. Three surgical pathologists interpreted them in a blinded manner for the histology diagnoses and E-cadherin staining. E-cadherin staining was conducted on the paraffin-embedded sections of the breast lesions using two different source antibodies. Our results using morphology and E-cadherin stain agreed with the previous diagnoses of lobular neoplasia and infiltrating lobular carcinoma in 140 of 161 cases (86.9%). Among the 140 cases, three pathologists agreed with the morphologic diagnoses of lobular neoplasia and infiltrating lobular carcinoma in 100 (71.4%), two pathologists in 26 (18.6%) and one pathologist in 14 (10%). All three pathologists disagreed with the previous diagnoses of lobular neoplasia and infiltrating lobular carcinoma but reevaluated as ductal lesions in 21 cases (13.0%). E-cadherin staining was confirmatory in 136 of total 161 cases (84.5%) of both lobular and duct lesions by showing the loss of staining in lobular lesions and the presence of complete membrane staining in duct lesions. Aberrant E-cadherin reactions were retained weak or partial incomplete thin membrane reaction in lobular-type lesions and reduced membrane reaction in ductal-type lesions were seen in 25 of the total 161 cases (15.5%). E-cadherin immunoreaction with two different antibodies showed discrepant results in 5 of 78 cases tested (6.4%). This study illustrates (1) interobserver variability of the morphologic diagnoses of lobular neoplasia/infiltrating lobular carcinoma and duct neoplasia/infiltrating duct carcinoma, (2) the occasional presence of aberrant E-cadherin stain pattern in these breast lesions and (3) variability of E-cadherin immunostaining results by two different antibodies.

Expression of E-cadherin in angiomyolipoma

“…E-cadherin was studied in a variety of tumors, mostly in epithelial tumors, such as colorectal carcinoma [9], endometrial carcinoma [10], breast carcinoma [11,12], ovarian carcinoma [13], and gastric carcinoma [14].…”

Application of Immunohistochemistry in Breast Pathology: A Review and Update

“…However, aberrant E-cadherin expression was identified in occasional lobular CA cases, which was reported in the range of 2% to 16%. [45][46][47][48][49] Harigopal et al 50 reported aberrant E-cadherin staining patterns in 5 invasive mammary CAs. In their study, the aberrant E-cadherin expression was defined as an E-cadherin immunophenotype that did not correspond to the apparent histologic classification of the lesion.…”

Primary Squamous Cell Carcinoma Of The Breast: A Case Report And Immunohistochemical Features For Differential Diagnosis

“…Cytokeratin profile in our case, especially diffuse CK7, CK8, CK19 and focal CEA positivity gives support to ductal origin of the tumor. [19][20][21][22] Moreover, the tumor displayed membranous E-cadherin staining which is characteristic of the ductal immunophenotype, [23,24] while HMW CK positivity, histologic appearance and lamellar keratin formation are typical properties of squamous cells.…”