[Inflammatory lesions of the breast: indication for MR-mammography?]

Magnetic resonance imaging of the breast: recommendations from the EUSOMA working group

The use of breast magnetic resonance imaging (MRI) is rapidly increasing. EUSOMA organised a workshop in Milan on 20-21st October 2008 to evaluate the evidence currently available on clinical value and indications for breast MRI. Twenty-three experts from the disciplines involved in breast disease management - including epidemiologists, geneticists, oncologists, radiologists, radiation oncologists, and surgeons - discussed the evidence for the use of this technology in plenary and focused sessions. This paper presents the consensus reached by this working group. General recommendations, technical requirements, methodology, and interpretation were firstly considered. For the following ten indications, an overview of the evidence, a list of recommendations, and a number of research issues were defined: staging before treatment planning; screening of high-risk women; evaluation of response to neoadjuvant chemotherapy; patients with breast augmentation or reconstruction; occult primary breast cancer; breast cancer recurrence; nipple discharge; characterisation of equivocal findings at conventional imaging; inflammatory breast cancer; and male breast. The working group strongly suggests that all breast cancer specialists cooperate for an optimal clinical use of this emerging technology and for future research, focusing on patient outcome as primary end-point.

Typical atypical findings on dynamic MRI of the breast

Dynamic contrast enhanced magnetic resonance imaging (DCE MRI) of the breast has become an important tool to detect and characterize breast disease. The American College of Radiology Breast Imaging Reporting and Data System (BI-RADS(®)) provides a standardized vocabulary for describing the morphologic features and contrast kinetics of breast lesions. However, some lesions may show morphologic and dynamic MR features not consistent with their histologic nature resulting in incorrect categorization as malignant or benign. Another cause of diagnostic problems is artifacts. Thus correct interpretation of dynamic MRI of the breast demands knowledge of the most common pitfalls encountered in clinical practice. A pictorial overview of these is presented, with particular reference to the differentiation of malignant tumors from benign lesions.

Undetected malignancies of the breast: dynamic contrast-enhanced MR imaging at 1.0 T

PURPOSE

To assess the prevalence and characteristics of malignant breast lesions not identified with magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Breast tissue specimens were obtained in 464 of 967 patients who had undergone dynamic gadolinium-enhanced T1-weighted fast low-angle shot three-dimensional MR imaging of both breasts. A comparison of sensitivity, specificity, and predictive values of the prospectively recorded findings of mammography, ultrasonography (US), and MR imaging with the histopathologic results was performed with receiver operating characteristic (ROC) curve analysis. MR imaging examination findings that caused a false-negative diagnosis were reviewed to identify possible sources of error.

RESULTS

Histopathologic analysis revealed 244 benign and 354 malignant lesions. The sensitivity values for mammography, mammography combined with US, MR imaging alone, and the combination of all three modalities were 73.7%, 88.1%, 88.4%, and 95.5%, and the areas under the ROC curves were 0.744, 0.829, 0.850, and 0.876, respectively. Twenty-eight (8.4%) of 334 invasive and 13 (65%) of 20 intraductal carcinomas were missed with MR imaging. In eight cases, motion artifacts (n = 1), tumor location near or beyond the outer boundary of the field of view (n = 3), inadequate infusion of the contrast material (n = 1), and masking of the tumors by intensively enhanced surrounding glandular tissue (n = 3) were identified as adequate explanations for the false-negative results. The remaining missed breast cancers (n = 33) exhibited very diffuse growth patterns or were 5 mm or smaller.

CONCLUSION

MR imaging did not depict 41 of 354 malignant tumors for several reasons.

Inflammatory Carcinoma of the Breast: Characteristic Findings of MR Imaging

Inflammatory breast carcinoma (IBC) Shows a unique clinical appearance and has an extremely poor prognosis. Although immediate intensive therapy has been proposed, diagnosis of this disease tends to be delayed as its clinical features can be confused with acute mastitis. The conventional imaging modalities including mammography and ultrasonography are of limited value in the diagnosis of IBC, as it is difficult to delineate specific findings of the swollen dense breast. Recently, magnetic resonance (MR) imaging has been widely applied to breast diseases. One of the excellent features of this modality is its diagnostic ability in dense breasts. However, few trials to evaluate the capability of this new modality for IBC have been documented. In recent years, we found that a characteristic feature in 5 cases of IBC was a strong signal on T2-weighted images (T2WI) of MR imaging at the retromammary and subcutaneous area. Pathological features of the retromammary area showed marked interstitial edema and focal lymphatic involvement by tumor cells. These characteristic images obtained by MR imaging may be suggestive of inflammatroy breast carcinoma. Furthermore, subtracted dynamic MR imaging indicated the site of the tumor. Therefore, the application of MR imaging for swollen breasts would assist in the immediate diagnosis of IBC and would contribute to appropriate and timely therapy.

MRI of the breast in the differential diagnosis of mastitis versus inflammatory carcinoma and follow-up

PURPOSE

Our goal was to evaluate the potential of dynamic MRI in differentiating mastitis and inflammatory breast carcinoma. Furthermore, we evaluated the potential of breast MRI to follow up mastitis patients under antibiotic treatment.

METHOD

Twenty-one cases of dynamic breast MR (11 mastitis, 10 inflammatory carcinomas) were reviewed. All patients had a history consistent with either mastitis or inflammatory breast carcinoma. The final diagnosis was histologically confirmed.

RESULTS

Ninety percent of the inflammatory carcinomas were found to enhance > 100% in the first minute compared with 55% for mastitis. There is no significant difference between mastitis and inflammatory carcinoma.

CONCLUSION

While breast MR cannot currently be used definitively to distinguish inflammatory carcinoma from mastitis, the differences in dynamic enhancement may prove to be useful in follow-up of presumed mastitis in problematic cases. If after biopsy the diagnosis remains unclear, breast MR may help to (a) demonstrate the success of the antibiotic treatment and (b) diagnose coexisting or confounding inflammatory carcinoma.