A comparison of large block macrosectioning and conventional techniques in breast pathology.

Two techniques for the histological handling of breast specimens, namely conventional sampling using small blocks (SB) and a large block (LB) macrosectioning technique have been compared, with special emphasis on tumour size and in situ carcinoma, in an attempt to objectively demonstrate the advantages of the latter method. This is considered to be of particular importance in guiding the clinicians in their use of the many treatment modalities available for breast carcinoma. All cases were from the routine surgical caseload; 100 examined by the LB technique and 111 using conventional SB. The LB technique gave a reliable measurement of invasive carcinoma in 100% of cases compared to only 63% of SB cases. Ductal carcinoma in situ (DCIS), was found more frequently (80% versus 64%) and its extent was more easily and reliably measured in the large blocks. The extent of DCIS was significantly greater in all cases using large block techniques. Concurrent carcinomas were found more frequently in the LB series and these tumours were smaller than those in the SB series. Similar differences were noted with radial scars, and other proliferative lesions also had a higher incidence in the LB series. We conclude that the LB technique has sufficient advantages to recommend it as a standard technique in breast pathology.