[Lymph node biopsy]

Lymph node biopsy is often easy to perform but final histologic diagnosis and accuracy depends on its technical quality: adequate biopsy and proper fixation and processing. This technical note defines advice on the selection of the lymph node biopsy site, shows the interest of a previous lymph node needle aspiration and gives the principles of histopathological techniques: cytology on imprints from the excised fresh unfixed node, fixation, staining methods ad immunohistochemistry. A place is given to the indications of frozen section diagnosis, frozen tissue, electron microscopy, microbiological, cytogenetic and molecular studies for gene rearrangement.