Clinicopathological features of invasive micropapillary carcinoma of the breast.

The aim of the present study was to evaluate the clinical and immunohistopathological findings of invasive micropapillary carcinoma (IMPC) of the breast. In total, 25 patients were included in the present study, all of whom were diagnosed with IMPC. The mammography and ultrasound scanning (US) findings were analysed retrospectively according to the American College of Radiology Breast Imaging Reporting and Data System lexicon. Surgical specimens obtained from the patients were microscopically reviewed in consensus by two pathologists with a specialisation in breast pathology. All the patients presented with palpable lumps in the breast, a high-density irregular mass associated with microcalcifications revealed by mammography and an irregular hypoechoic mass with a spiculated margin revealed by US. Axillary lymph node metastases were identified in 80% of the patients. Immunohistochemical studies revealed the lesions to be highly positive for the oestrogen receptor (ER) and c-erbB-2 (88% and 84%, respectively). Although no significant imaging characteristics were found to distinguish IMPC from typical invasive ductal carcinoma, IMPC resulted in nodal metastases and was highly positive for ER and c-erbB-2. This clinical significance indicates the significance of this entity being recognised by pathologists and surgeons.