Medullary carcinoma of the breast

Clinical History

A 60-year-old female presented with a mass on the right breast.

Imaging Findings

A 60-year-old woman consulted her physician as she noticed for a palpable mass on the right breast on self exam. The following radiographic examinations were performed: A mammography, ultrasonography and MR imaging. Mammographies of the right breast showed the presence of a mass of 30 mm; mammographies of the left breast revealed no suspicious findings. An US of the right breast showed the presence of a nodule of 27 mm. Dynamic subtraction MR-imaging, after gadolinium injection, displayed a mass with areas of early enhancement and a cystic space. A biopsy of the mass was performed, which confirmed the histology of the lesion.

Discussion

Medullary carcinoma is an infrequent type of mammary duct carcinoma (5%–7% of breast cancer), age range-median varies from 46 to 54 years, and it is usually considered to have a better prognosis than the common forms of an infiltrating duct carcinoma. However, there is a subtype of medullary carcinoma called “atypical medullary” that does not have a favorable prognosis. The diagnosis of a typical medullary carcinoma was made based on the following five characteristics: syncytial architecture >75%; complete histologic circumscription; moderate, marked and diffuse mononuclear cell infiltration; moderate or marked nuclear pleomorphism; and absence of microglandular structure. Atypical medullary carcinoma diagnosis is done with syncytial architecture >75%, which is associated with 2 or 3 of the other characteristics. At presentation, medullary carcinomas are often large and well circumscribed. The World Health Organization defines medullary carcinoma of the breast as “a well-circumscribed carcinoma composed of poorly differentiated cells with scant stroma and prominent lymphoid infiltration”. Central necrosis secondary to hemorrhage is a common feature. Medullary carcinomas rarely contain calcification because there is no intraductal component within the tumor. The mammographic appearance of a medullary carcinoma of the breast is that of a uniformly dense, round or oval, noncalcified mass with lobulated margins. An ultrasound analysis of the medullary cancers has shown their tendency to be round, to have smooth contours, and to have weak or absent internal echoes with little or no attenuation. Medullary carcinomas generally cause less attenuation of sound than other malignant tumors do. Many other US features which were previously considered to be more typical of benign tumors, such as a smooth contour, weak internal echoes, and round or oval shape, have been identified as well. Although there were no specific sonographic features for a definitive diagnosis, the appearence of the tumor margins was statistically significantly different between typical and atypical medullary carcinomas. In cases where sonography shows jagged margins or margins with focal irregularity, particularly if acoustic shadowing is present, a careful pathologic evaluation of the entire tumor is necessary to establish an accurate diagnosis.

Differential Diagnosis List

Final Diagnosis

Medullary carcinoma of the breast.

URL:	https://www.eurorad.org/case/2421
DOI:	10.1594/EURORAD/CASE.2421
ISSN:	1563-4086