Senile changes in human lymph nodes

Introduction: Our general knowledge of the structure and function of the lymph node is based mostly on studies of the solidified lymph nodes. However, a recent study has described transparent lymph nodes.1 It is therefore timely to further investigate lymph node anatomy and its relevance for clinical application. Methods: A total of 161 lymph nodes from the superficial tissues of the head and neck of seven fresh human cadavers and one embalmed human cadaver aged between 81–98 years were studied. We used 6% hydrogen peroxide to find the distal lymphatics, injected the vessels with a lead oxide, milk powder and water mixture and then X-rayed them 2. We traced the injected lymphatic vessels to their related nodes and found both solidified and transparent lymph nodes. The lymph nodes were removed from the specimens, fixed in 10% nature buffered formalin and sent for histopathological cross section. Histopathology slides were viewed and photographed. The data were then transferred to a computer for analysis. Results: Thirty eight solidified and 123 transparent lymph nodes were found. A series of histopathological sections show that the degenerative process is continuous - from the solidified node to the transparent nodes. The senile involution affected all elements of the lymph node including the cortex and medulla. The lymph nodes in different degenerative stages show different structures and appearance on histopathological section. Conclusion: This study provides anatomical and histopathological images of lymph nodes in different degenerative stages in the head and neck region of the elderly. It may help explain some clinical conditions in the elderly especially their diminished immunological response to infection and cancer metastasis.