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Magnetic resonance imaging (MRI) of the breast is used for select groups of patients. MRI-guided breast core needle biopsies performed over a 3-year period were retrospectively reviewed to determine the incidence and types of cancers found and to correlate the cancers with the MRI findings and the indication for the study. Patients were stratified based on indication for MRI examination including, evaluation of disease extent in patients with current ipsilateral carcinoma, surveillance for recurrence of prior ipsilateral carcinoma, as a problem-solving method and for screening high-risk patients. The high-risk screening group included those with family history (with or without germline mutations), prior chest wall radiation, and contralateral breast carcinoma (current or prior). Four-hundred and forty-five biopsies were performed on 386 patients. The majority of biopsies (79%) were benign. Biopsies demonstrating ductal carcinoma in situ (DCIS) and invasive carcinoma were more likely to present as nonmass-like and mass-forming enhancements respectively, but with only 52% specificity. The highest rate of malignancy (44%) was seen in the least frequently biopsied patient group (n = 25), those with prior ipsilateral carcinoma. Conversely, the most frequently biopsied group (n = 283), the high-risk screening group, demonstrated the lowest malignancy rate (16%). Within this group, most malignant cases were invasive carcinomas (n = 27), 67% of which were small (≤1 cm), well or moderately differentiated with a good prognostic receptor profile (estrogen receptor positive, human epidermal growth factor receptor 2 negative), and lacked nodal macrometastases. The remaining malignant cases in the high-risk screening group were DCIS with or without microinvasion (n = 18), 78% of which demonstrated high nuclear grade. Overall, enhancement pattern did not correlate with the likelihood of or type of malignancy. The most common types of carcinomas identified by screening were small estrogen receptor positive invasive tumors and high grade DCIS., (© 2014 Wiley Periodicals, Inc.)

HER2/neu status in breast cancer is determined by immunohistochemical analysis and/or fluorescence in situ hybridization (FISH). Previous studies have found widely varying sensitivities and specificities for anti-HER2/neu antibodies, including recently developed rabbit monoclonal antibodies. The current prospective study compared rabbit monoclonal antibody SP3 and rabbit polyclonal antibody A0485 immunostaining on routinely processed consecutive cases of breast carcinoma. Of 1,610 cases tested, 261 (16.2%) equivocal (2+) cases were evaluated by FISH. Of 253 cases equivocal with A0485 results, 125 (49.4%) were negative with SP3. In 22 (8.7%) of 253 cases equivocal with A0485, there was amplification by FISH, and 3 of these cases were SP3- (0/1+). Of the 20 (14.8%) of 135 SP3-equivocal cases amplified by FISH, 1 case was A0485-. The reported false-negative rate with A0485 is 2.8%, and the American Society of Clinical Oncology/College of American Pathologists guidelines recommend a rate of less than 5%. Compared with A0485, the false-negative rate with SP3 is only 0.3% (3/1,156) higher, but it shows about a 50% reduction in equivocal scores, reducing the need for reflex FISH testing.

The following abstracts are compiled from Check Sample exercises published in 2008. These peer-reviewed case studies assist laboratory professionals with continuing medical education and are developed in the areas of clinical chemistry, cytopathology, forensic pathology, hematology, microbiology, surgical pathology, and transfusion medicine. Abstracts for all exercises published in the program will appear annually in AJCP.

Second opinion in pathology is intended to expose clinically significant errors that have a direct impact on patient care. Before definitive treatment of referred patients, our institution requires a second opinion of outside surgical pathology slides. We sought to determine if this local standard of practice has a measurable impact on patient care via clinical and pathologic follow-up. 5629 second opinion surgical pathology cases seen at the University of Iowa Hospitals and Clinics were studied. Each case was classified as: no diagnostic disagreement, minor diagnostic disagreement, or major diagnostic disagreement by the second opinion pathologist at the time of referral. A major diagnostic disagreement was defined as a change in pathologic diagnosis with potential for significant change in treatment or prognosis. Major diagnostic disagreements were categorized by organ system and according to the clinical significance of the changed diagnosis based on clinical and pathologic follow-up. Second opinion surgical pathology resulted in 132 (2.3% of total cases) major diagnostic disagreements and 507 (9.0%) cases with minor disagreements. The organ systems involved in the majority of the major disagreements were the female reproductive tract (32), gastrointestinal tract (27), and skin (24). Of the 132 major diagnostic disagreements, 68 (1.2% of total cases reviewed) prompted changes in the clinical management as a result of the second opinion interpretation. These findings support the idea that mandatory second opinion is an important part of patient care in the referral setting.