Use Of Immunohistochemical Analysis Of Ck5/6, Ck14, And Ck34betae12 In The Differential Diagnosis Of Solid Papillary Carcinoma In Situ From Intraductal Papilloma With Usual Ductal Hyperplasia Of The Breast

Objectives: The aim of this study was to use immunohistochemistry to differentiate solid papillary carcinoma in situ from intraductal papilloma with usual ductal hyperplasia (IPUDH). Three types of high-molecular-weight cytokeratins (CKs) - CK5/6, CK14, and CK34betaE12 - were targeted. Methods: We studied 17 patients with solid papillary carcinoma in situ and 18 patients with IPUDH diagnosed by at least two pathologists. Immunohistochemical analyses used antibodies to CK5/6, CK14, and CK34betaE12 to make the differential diagnosis of solid papillary carcinoma in situ versus IPUDH. Immunohistochemical staining was scored as 0-5 using Allred score. Results: Immunohistochemistry with CK5/6 and CK14 antibodies produced scores of 0-3 in all patients with solid papillary carcinoma in situ and 2-5 in all patients with IPUDH. Immunohistochemical staining with CK34betaE12 antibody produced scores of 1-3 in all patients with solid papillary carcinoma and 3-5 in all patients with IPUDH. In tissues from patients with IPUDH, significantly more cells were stained with CK34betaE12 than CK5/6 (p < 0.05) or CK14 (p < 0.05). Conclusion: The immunoreactivity of CK5/6, CK14, and CK34betaE12 antibodies was useful to differentiate solid papillary carcinoma in situ from IPUDH. CK34betaE12 is especially useful for distinguishing solid papillary carcinoma from IPUDH.