How can we distinguish between reactive hyperplasia and neoplastic changes in lymph nodes?

To distinguish between reactive hyperplasia and neoplastic changes in lymph nodes, the most effective method is through the microscopic assessment of lymph node architecture and cellular features.

In reactive hyperplasia, the lymph node typically shows an increased number of lymphocytes, often with a preserved architecture where the follicles are well defined and maintained. The distribution of different cell types within the node, such as lymphocytes, plasma cells, and histiocytes, can appear uniform and organized. Changes like increased mitotic activity can be observed but are usually still within a normal range for reactive processes.

In contrast, neoplastic changes often result in disorganized architecture with atypical cell populations. Neoplastic lymph nodes may exhibit expansion of certain cell types, loss of the normal follicular structure, pleomorphism, and increased cellularity that is inconsistent with normal reactive patterns. Furthermore, there may be evidence of invasion into surrounding tissues or metastasis, depending on the type of neoplasm.

The other options, while they may provide useful information, do not directly assess the cellular characteristics and organization essential for differentiating between these two conditions. Evaluating the size and shape of lymph nodes can provide some context but is not definitive in characterizing the underlying pathology. Blood tests for tumor markers can sometimes