A Case of an Invasive Lobular Carcinoma with Extracellular Mucin: Radio-Pathological Correlation

A case of 77-year-old female with an invasive lobular carcinoma with extracellular mucin is presented. She felt palpable mass in her left breast. Then, she came to our hospital for further examination. Mammography of right in full view revealed architectural distortion in left upper portion. And ultrasonography demonstrated low-echoic mass about 2 cm in diameter and invasion of the fat tissue was observed. Hence, malignancy was suspected and magnetic resonance imaging (MRI) was performed. MRI findings showed irregular shaped and margined mass with small T2-high-signal intensity. These findings suggested invasive carcinoma with mucin. Because the cancer lesion was not large, partial mastectomy was performed. Interestingly, pathological diagnosis was invasive lobular carcinoma with extracellular mucin. Extracellular mucinous lesion was concordant with small T2-high-signal intensity. This type of carcinoma was previously reported only in three cases, and rare but important, because the treatment and prognosis might change by histological subtypes. We suggest one of the MRI special features of our case is not only irregular shaped and margined mass but also small T2-high-signal intensity. These MR findings might be one of the valuable findings for the diagnosis and differentiation between this type of carcinoma from other tumors

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