(A) This lymph node is almost completely replaced by tumor nests recapitulating the pattern seen in the breast tissue. (Hematoxylin and eosin, original magnification ×40.) (B) This micrometastatic focus of tumor in a lymph node shows a tiny papillary structure and is somewhat subtle on low-power examination. (Hematoxylin and eosin, original magnification ×10.)
