LYMPH-NODE MICRO-METASTASIS - AN INVESTIGATION, INCLUDING 3-DIMENSIONAL RECONSTRUCTION

The mechanism by which malignant cells metastasise to, and colonise, r egional lymph nodes is not known. In an attempt to characterise micro- deposits an affected lymph node associated with a primary intra-oral s quamous cell carcinoma was studied. Three-dimensional reconstructions of the node and micro-tumour were made and the relationships and distr ibution of apparently isolated malignant cells present within the node studied. Semi-serial ethanol-fixed paraffin wax sections of the node were stained with monoclonal antibody AE3 (cytokeratin). Outlines of t he node and occupying micro-tumour were traced onto polystyrene tiles and onto acetate sheets, permitting the construction of both a solid a nd a transparent three-dimensional model. Additionally, the positions of apparently 'isolated' AE3-positive malignant cells were noted. The solid reconstruction showed that the micro-tumour deposit grew most qu ickly into the node via the septa and more slowly around the subcapsul ar region. The transparent reconstruction was less useful. Most isolat ed, individual malignant cells were found in the peripheral margin of the node.