Invasive Micropapillary Carcinoma of the Breast: Mammographic, Sonographic and MR Imaging Findings

Abstract

Purpose :We performed this study to investigate the characteristic imaging and clinicopathologic features of invasive micropapillary carcinoma of the breast. Materials and Methods:Among the 47 women with surgically confirmed invasive micropapillary carcinoma between 2005 and 2009, 32 patients (mean age, 50 years; range, 37-69 years) had all preoperative mammography, ultrasound (US) and MR images. Two radiologists retrospectively assessed the imaging findings, clinical presentation and histological results of the patients. Results:On mammography, 29 of 32 patients had suspicious findings. Among them, a mass (or focal asymmetry) with calcifications was the most common findings (15/32, 65%). The calcifications were noted in 20 patients (63%) and the shape of calcifications was frequently amorphous or punctate (n = 12, 60%). On US and MR imaging, all lesions had suspicious findings. The most common US findings were single (n = 20) or multiple (n = 10) irregular hypoechoic mass (es). The mass was frequently hypoechoic (n = 29, 97%). On MR imaging, the type of lesions was a mass or masses in 23 (72%), a mass combined with non-mass in six patients, and non-mass lesions in three patients. Histologically, axillary lymph nodes metastasis were very common (25/32, 78%). Asymptomatic clinical presentation was not usual (9/32, 28%). Conclusion:The imaging features of invasive micropapillary carcinomas strongly suggest malignancy. Microcalcifications on mammography, marked hypoechogenicity on US and an irregular mass, often combined with non-mass on MR are common. Axillary lymph node metastasis is commonly associated.

Micropapillary Breast Carcinoma: From Molecular Pathogenesis to Prognosis

“… 118 , 132 Patterns of single or multiple irregular mass with rapid washout waveforms are the most well-recognized patterns of IMPC presentation in MRI. 125 , 128 Mass and non-mass enhancement have also been previously described, while not as frequently as a solitary enhancing mass presentation. 91 , 119 , 122 The probability of a non-mass enhancement of the lesion being found in MRI ranges from 16.7% to 38.9%.…”

“… 124 Mammographic evaluation has a clear trend to underestimate the true disease size when IMPC is concerned. 97 , 98 , 122 False-negative rates in mammography evaluation have been reported as high as 12% for IMPC patients, 125 whereas patients with Invasive Lobular Carcinoma have false-negative rates higher than 14%, 126 and up to 19%. 127

Figure 3 ( A ) Preoperative and pre-treatment MRI image of IMPC.

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“… 128 , 133 Multifocal IMPC lesions are also better diagnosed and more accurately staged with MRI, compared to any other modality. 43 , 91 , 98 , 122 , 125 , 128 , 133 While MRI may be the best imaging modality for IMPC, there is still a percentage of lesions that will be missed, especially diffuse multifocal lesions with extensive DCIS or residual disease after PST. 117 , 134 An example of pre- and post-PST MRI imaging of micropapillary carcinoma can be seen in Figure 3 .…”