To investigate ultrasonic findings of pure invasive micropapillary carcinoma (PIMPC) of breast.

A total of 18 patients with surgically confirmed PIMPC and 40 patients with surgically confirmed invasive ductal carcinoma (IDC) treated between January 2010 and August 2015 in Affiliated Union Hospital of Fujian Medical University, who had undergone preoperative ultrasound examination, were included in the study. To compared with the postoperative pathological examination, the value of ultrasonography in the diagnosis of axillary lymph node metastasis was discussed. Ultrasound findings of PIMPC and pathological results were compared.

Ultrasound analysis of PIMPC masses identified predominantly hypoechoic lesions and irregular shape 100% (18/18), obscure lesion boundaries 88.9% (16/18), spiculated or angular margins 83.3% (15/18), combined microcalcifications 83.3% (15/18), with posterior acoustic enhancement or normal 88.9% (16/18), dcrab claws changes 77.7% (14/18), witout hyperechoic halo72.2% (13/18) and with 0-?Ⅰ grade flow signals 55.6% (10/18). Compared to the IDC, the PIMPC had lower proportions in long speculation, hyperechoic halo, aspect ratio≥0.7, posterior echo attenuation, Ⅱ-Ⅲ grade blood flow signals (P<0.05), while their lesions in the maximal tumor size, shape, boundary, edge bur, microcalcification has no significance (P>0.05). The rate of lymph node metastasis of PIMPC was 72.2% (13/18), which was significantly higher than that of IDC 45.0% (18/40) (t=3.697, P=0.05). 13 cases were pathologically confirmed lymph nodes metastasis in 18 cases, and among them, the ultrasound indicated abnormal 46.2% (6/13), and showed abnormal cortex and medulla structure 30.8% (4/13), eccentric lymph door 30.8% (4/13), poor blood flow signals 38.5% (5/13). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PIMPC lymph node metastasis by preoperative ultrasound were respectively 46.2%, 60.0%, 75.0%, 30.0%, 50.0%. Ultrasound performance of PIMPC has a certain relationship with its special pathological characteristics. Sonography findings were compared with pathological results: Microscopically, PIMPC cell arranged as pseudo-papillary or tubuloalveolar structures floating in empty spaces; PIMPC with 0-Ⅰ grade flow signals were seen that the small amount of new blood vessels of the tumor were mainly found in the pellucid zone around the cell clusters under the microscope, while IDC with Ⅱ-Ⅲ grade blood flow signals were found that more regenerated blood vessels were distributed in the collagen fibers. PIMPC witout hyperechoic halo were noticed that under the microscope, there were no fibrous tissue clusters in the edge of the tumor, meanwhile, IDC with hyperechoic halo were discovered that fibrous tissue was seen at the edge of the mass of the lens.

Ultrasound performance of PIMPC has a close relationship with its special pathological characteristics. To be familiar with ultrasound characteristic of PIMPC is significant for improving its ultrasound detection rate.