Mammographic Localization Biopsy for Ductal Carcinoma In Situ: A Simple Mapping Technique for Sampling and Size...

Size, grade, margin status, and microscopic invasion are currently significant parameters for management of ductal carcinoma in situ (DCIS). Size estimation of DCIS is difficult or impossible if tissue is sampled haphazardly. Histologic examination of the entire biopsy to exclude microscopic invasion is cumbersome and expensive, and may not yield more information than less extensive but planned sampling. One hundred twenty-four mammographic localization biopsies with DCIS including 4 cases with 3 mm or less invasion are presented to address these issues. All were examined by a mapping technique utilizing specimen radiograph as a guide for sampling and a schematic drawing to record the sections. This involved sequential sampling of the entire tissue for smaller biopsies, and en bloc sampling of the mammographic abnormality and surrounding tissue with end-to-end sampling of the remaining tissue at regular intervals for larger biopsies. All tissue was examined histologically initially in 55 cases, while tissue away from the lesion was selectively omitted in 71 cases. To address the issue of occult invasion, all initially unsampled tissue of 44 biopsies was submitted for histologic examination after completion of the case and the findings were recorded separately. Size estimates ranged from 4 to 70 mm. The solitary focus of microscopic invasion in four cases was present in the initial sections at the site corresponding to the mammographic abnormality. No invasion was identified in the additional tissue in any of the 44 cases. Margin status did not change for any. Using specimen radiographs as a guide, all the necessary information for DCIS, including the size and microscopic invasion, can be obtained by a planned sampling of tissue with diagrammatic documentation. Sequential sections of the entire tissue for small biopsies and sampling at regular intervals to include tissue at and around the mammographic abnormality for larger biopsies is appropriate. Microscopic invasion, when focal, is likely to be identified at the site of mammographic abnormality in the initial en bloc sections.