Radiological-pathological correlation in diagnosing breast carcinoma: the role of pathology in the multimodality era.

Breast carcinoma is a lobar disease, as the simultaneously or asynchronously appearing often multiple tumor foci originate from a single sick breast lobe. In its initial phase, the spatial pattern of malignant transformation may be lobar (targeting the entire lobe), segmental (targeting a segment) or terminal (targeting distant terminal ductal-lobular units) within the sick lobe. All these variations are properly characterized by the following parameters: the extent of the disease (the volume of the tissue containing all the actually present malignant structures within the breast), the distribution of the lesions within this tissue (unifocal, multifocal or diffuse, separately for in situ and invasive component), the size of the tumor (corresponding to the largest diameter of the largest invasive focus) and the exact localization of the lesion(s). In addition, intra- and intertumoral heterogeneity have to be noticed, if evident. Combining the results of different imaging modalities (mammography, ultrasound, magnetic resonance imaging) the radiologist may compensate the limitations of individual methods. This multimodality approach leads to more accurate radiological size measurement, more accurate assessment of the distribution of the lesions and disease extent. This represents a challenge for pathologists as the traditional histopathology method based on fragmentation and sampling of macroscopically suspicious lesion(s) is clearly insufficient for modern postoperative radiological-pathological correlation. There is a clear need for more complete examination of the excised tissue and for a three-dimensional reconstruction of the finding, preferably using continuous large tissue slices and two and three-dimensional large-format histological sections. Discordant results may still appear as a consequence of failure in radiological-pathological correlation or related to certain tumor subtypes as invasive lobular carcinoma of diffuse type, low grade in situ lesions or micropapillary ductal in situ carcinoma.