Skip lesions in the axilla in breast cancer, and their association with micrometastases

The term 'skip lesion', referring to a tumour-bearing node in the axilla in breast cancer, presupposes that nodal colonization usually occurs in sequence with the path of the lymph flow. Skip lesions are thus out of step with the system. The present study of axillary nodes from 73 node-positive patients demonstrates that skip lesions have much in common with lone micrometastases found at any level, and are thus but a variant of the pattern found in early colonization of the axilla. This in turn indicates that in contrast to a progressive build up of tumour growth first at the lower and later at the middle level, early colonization may be a random process. This again stresses the importance of nodal dissection versus biopsy in the management of breast cancer, particularly in view of recent reports on the prognostic significance of micrometastases.