Radiologic findings of lobular carcinoma in situ: mammography and ultrasonography

Approach to Nonmass Lesions on Breast Ultrasound

Nonmass lesions in breast ultrasound (US) are areas of altered echogenicity without definite margins or mass effect. However, these lesions may show calcifications, associated architectural distortion, or shadowing just like masses. They vary in their echogenicity, distribution, ductal or nonductal appearance and the associated features that can be seen in variety of benign and malignant pathologies. With no uniform definition or classification system, there is no standardized approach in further risk categorization and management strategies of these lesions. Malignant nonmass lesions are not uncommon and few sonographic features can help in differentiating benign and malignant pathologies. US-guided tissue sampling or lesion localization can be preferred in the nonmass lesions identified on second look US after magnetic resonance imaging or mammography. This article aims to describe various imaging patterns and attempts to provide an algorithmic approach to nonmass findings on breast US.

Characterization of Breast Microcalcifications Using a New Ultrasound Image-Processing Technique

OBJECTIVES

To evaluate a new commercial image-processing technique (MicroPure; Toshiba America Medical Systems, Tustin, CA) for detection and characterization of breast microcalcifications in patients undergoing stereotactic or ultrasound-guided biopsies using mammography as the reference standard.

METHODS

One hundred female patients, with a total of 104 lesions, scheduled for an image-guided biopsy of an area with breast microcalcifications (identified on a prior mammogram) underwent MicroPure examinations of the breast using an Aplio XG scanner (Toshiba America Medical Systems) with a broad-bandwidth linear array. MicroPure combines nonlinear imaging and speckle suppression to mark suspected calcifications as white spots in a blue overlay image. Four independent and blinded readers (2 radiologists and 2 physicists) analyzed 208 digital clips consisting of dual grayscale ultrasound and MicroPure imaging, counting the number of microcalcifications seen with MicroPure. The observers also assessed the level of suspicion on a qualitative, visual analog, 6-point scale from 0 (no findings) over 1 (benign) to 5 (malignant).

RESULTS

The mean number of microcalcifications ± SD seen was 6.3 ± 3.5, whereas mammography saw 28.9 ± 24.6 (P = .66). When the MicroPure level of suspicion scores were compared with pathologic results using a receiver operating characteristic curve analysis, the areas under the curve ranged from 0.54 to 0.59. Nonetheless, malignant cases were seen to have significantly more microcalcifications than benign cases (mean number of microcalcifications, 6.9 ± 5.1 versus 5.3 ± 3.7; P = .02).

CONCLUSIONS

MicroPure can be used to identify areas with breast microcalcifications but cannot effectively characterize such areas. Instead, MicroPure may represent a new imaging method for guiding a biopsy to areas of microcalcifications.

Management of atypical lobular hyperplasia, atypical ductal hyperplasia, and lobular carcinoma in situ

Atypical hyperplasia and lobular carcinoma in situ are rare proliferative breast lesions, growing inside ducts and terminal ducto-lobular units. They represent a marker of increased risk for breast cancer and a non-obligate precursor of malignancy. Evidence available on diagnosis and management is scarce. They are frequently found incidentally associated with other lesions, but can be visible through mammography, ultrasound or magnetic resonance. Due to the risk of underestimation, surgical excision is often performed. The analysis of imaging and histopathological characteristics could help identifying low-risk cases, for which surgery is not necessary. Chemopreventive agents can be used for risk reduction. Careful imaging follow up is mandatory; the role of breast MRI as screening modality is under discussion.

Histopathologcial and clonal study of combined lobular and ductal carcinoma of the breast

Lobular carcinoma in situ (LCIS) clinically constitutes a risk factor for the subsequent development of either invasive lobular carcinoma (ILC) or invasive ductal carcinoma (IDC). In order to approach the possibility of this common precursor of both ILC and IDC, we investigated combined lobular and ductal carcinomas. Thirty-two cases of lobular carcinoma were picked up out of 773 cases of operated breast carcinomas. The histopathological detailed re-examination using immunostain of E-cadherin and β-catenin revealed a rather high frequency of combined lobular carcinomas than previous reports. Clinicopathologically, combined lobular carcinomas were younger and smaller than pure lobular carcinomas, and the cytological atypia was relatively low. These results suggested that combined lobular carcinomas could be detected in the earlier stage of breast cancer. Furthermore, the lobular and ductal components of combined carcinomas coexisted in the neighborhood and were distributed contiguously. The immunohistochemical phenotypes of both components were accorded in most combined cases. A genetic analysis using methylation-specific PCR on the HUMARA gene demonstrated that the same allele was inactivated in both lobular and ductal components in all detectable cases of combined carcinoma. Therefore, it is reasonable to assume that both lobular and ductal components of combined carcinomas are clonal and derived from the LCIS as the common precursor lesion, which may contradict the conventional concept that the lobular and ductal carcinomas arise from distinct differentiation pathways.

New image processing technique for evaluating breast microcalcifications: a comparative study

OBJECTIVES

The purpose of this study was to evaluate a new commercial image processing technique (MicroPure; Toshiba America Medical Systems, Tustin, CA) for identifying breast microcalcifications compared to gray scale ultrasound imaging (US) using mammography as the reference standard.

METHODS

Twenty women, with breast calcifications identified mammographically, underwent gray scale US and MicroPure examinations of the breast. Still images and digital clips of the target area were acquired using gray scale US and MicroPure (at 3 different sensitivity levels: 0, 1, and 2). The images were analyzed by 4 independent and blinded readers (2 radiologists and 2 physicists) to determine the number of calcifications as well as to score image quality and artifacts.

RESULTS

For all 4 readers, there were significantly more calcifications seen with MicroPure (at the 2 highest sensitivity levels) compared to gray scale US (P < .009). Agreement between readers consistently increased from gray scale US to MicroPure imaging (gray scale intraclass correlation coefficient, 0.02-0.44; versus MicroPure intraclass correlation coefficient, 0.34-0.71). The agreement improved between mammography and MicroPure (13.2%-28.3%) when compared with mammography and gray scale US (1.7%-5.2%); the 2 radiologists saw a bigger improvement. Two readers preferred the MicroPure image quality over gray scale US (P < .001) and vice versa for the other 2 readers(P < .001). All 4 readers saw fewer artifacts with MicroPure (at level 2) than with gray scale US (P < .02).

CONCLUSIONS

MicroPure imaging identified significantly more breast microcalcifications than gray scale US.