Large paraffin sections and chemical clearance of axillary tissues as a routine procedure in the pathological examination of the breast.

The technique of large paraffin sections of the breast and lymph node dissection of axillary tissues after chemical clearance as used in a routine histology laboratory is described and discussed. The findings in 155 cases of breast malignancy derived from routine surgical patients and also from the breast screening clinic are described and analysed. There were 21 cases of in-situ carcinoma alone and an additional 17 cases with minimal invasive carcinoma (MIC). The maximum area of each lesion in one plane was measured and the size varied between less than 1 cm2 and 30 cm2, with an average of 7 cm2. The large lesions had the highest incidence of MIC. There were 117 palpable invasive carcinomas and they were divided into two groups, namely single quadrant (80%) and multiquadrant malignancy (20%). The clinical implications of this are discussed. Lymph node metastases were found in 36 (27%) of all invasive carcinomas but no metastases were found in either in-situ carcinoma alone or when combined with MIC in the eight cases which had a radical operation.