Tetrahedron radiography of the microcalcifications of comedo ductal carcinoma in situ: three-dimensional assessment of surgical excision

A series of 45 chilled surgical specimens containing comedo ductal carcinoma in situ (DCIS) of the breast with prominent microcalcifications was radiographed in the laboratory from four viewpoints in a rigid tetrahedron. There was considerable variation (0–22 mm) in the distances between the surgically resected edge and the microcalcifications. The least satisfactory view, and the one displaying the greatest variance was the conventional projection with the specimen laid flat with its minimum axis parallel to the X-ray beam (mean distance between outermost microcalcification and specimen EDGE = 7.2 mm; SEM 0.82). The other three views showed closer proximity of the microcalcifications to the plane of surgical excision (< 5 mm) in 19/45 of specimens where the clearance from the microcalcifications in the conventional view was> 5 mm. The implications are that this radiographic method in the laboratory can enhance critical evaluation of surgical resection by identifying the appropriate planes for histological examination.