Prepared by Dr. Margolies, Assistant Professor of Radiology and Director of Breast Imaging, The Mount Sinai Medical Center, New York, NY.
The patient is a 32-year-old nulliparous woman who complained of a new painless palpable mass in her left breast. She had no family history of breast cancer. Mammography was ordered.
On mammography, multiple masses with numerous microcalcifications were found. Two areas were selected for stereotactic biopsy, and both samples were revealed to be poorly differentiated breast cancer (Figure 1). Preoperative magnetic resonance imaging (MRI) showed the cancer as a mass with irregular margins (Figures 2 through 4). The mass had heterogeneous enhancement including washout kinetics, which is typical for breast cancer (Figure 5). The index mass exhibited all 3 classic MRI features of breast cancer: abnormal morphology, abnormal enhancement, and an abnormal washout kinetic enhancement pattern (Figures 2 through 5). No additional lesions were identified.
Ductal carcinoma and infiltrating lobular carcinoma
At surgery, the patient was found to have a mixed, infiltrating, predominantly poorly differentiated ductal carcinoma and infiltrating lobular carcinoma with an extensive intraductal component and extensive lymphatic invasion. The tumor was estrogen- and progesterone-recep-tor-positive, and the immunohistochemical stain for HER-2-NEU onco- protein was positive. The sentinel lymph node indicated microscopic metastatic disease. While the patient was a candidate for breast conservation therapy, she elected to undergo a mastectomy.
Approximately 5% of newly diagnosed breast cancers occur in women under the age of 40 1 who do not undergo screening unless they are at high risk. In this age group, women who have breast cancer most often present with a painless palpable mass. Patients younger than age 36 usually have larger tumors and more nodal involvement and are likely to have stage II or III cancers at presentation. Poorly differentiated cancers are more common in the younger population, and these patients are more likely to undergo mastectomy. 1,2 In one study, 12% of these young patients were found to have a contralateral breast cancer at the time of diagnosis or to have developed it later. 3
Multiple studies have reported the ability of breast MRI to detect breast cancers that mammography and sonography have missed. In an analysis of multiple published papers, Peters et al 4 found a 90% sensitivity and a 72% specificity for contrast-enhanced MRI. In women who have been found to have breast cancer, additional cancers in the same breast have been found in 11% to 31% of women. 5 A study by Pediconi and colleagues 6 reported that 24% of 118 patients with breast cancer had a contralateral breast cancer that was detected only by MRI-ie, missed by mammography and ultrasound. The majority of the additional cancers occurred in patients with heterogeneously dense or extremely dense breasts. 6 Some advocate preoperative MRI for the assessment of tumor extent and to determine the presence or absence of additional foci of tumor in the same or the contralateral breast. Others, however, are concerned that the additional foci of cancer that are found may not be significant and may not impact survival. They note that there have been no randomized trials to show an improvement in disease-free survival. 7,8 The role for preoperative MRI in breast cancer is yet to be determined; more studies are forthcoming.
Breast cancer in women who are too young for mammographic screening is often detected by self-examination. It is often diagnosed at a later stage and carries a worse prognosis than screening-detected cancers. It is incumbent on radiologists to remind our primary care colleagues to pursue radiology work-up of palpable findings in young women.
MRI finds cancers that are missed by mammography and ultrasound. Preoperative MRI shows additional foci of cancer, including ipsilateral and contra lateral cancers in a significant number of patients, and should be considered for presurgical planning for patients newly diagnosed with breast cancer.