Carcinoma Micromets

Carcinoma micrometastases (micromets) consist of small groups of cancer cells, originating from the original tumor site, that have spread through the lymphovascular system to another part of the body. The presence of metastasis in sentinel lymph nodes (SLN) may be the first indicator that cancer has spread to other sites in the body and is an important prognostic indicator. Histologic evaluation of lymph nodes using a microscope is the most accurate way to assess for lymph node metastasis, since a significant number of patients have clinically negative lymph nodes. Histologic evaluation involves taking sectioning of the tissue block at three different levels and staining each level with H&E and one of the levels with Pan-Cytokeratin (AE1/AE3) immunohistochemical (IHC) stain. Pan-Cytokeratin is an epithelial cell marker and is used to highlight small tumor cell clusters that may be difficult to detect based on H&E-stain alone.