Hello everyone, how are you all? Hope you all are doing well and great and i too. I hope you have read my previous post and you understand now i am going to tell about interesting topic today.

What is lymph node?
It is a small bean-shaped structure that is part of the body's immune system and if you palpate around neck region when you got fever, cold etc you will find small firm to hard structures and those are the lymph nodes.
In case of cancers of thyroid gland, breast etc.. these cancer cells will spread throught lymphatic system and they will reach lymph nodes and these tumor cells gets deposited there. This deposition of cancer cells in lymph nodes from primary breast cancer and thyroid cancer is called metastasis.
These lymph nodes which got these tumor or cancer cells deposition in it are called metastatic lymph node.

Normal histology of lymph node

Lymoh node has follicles which can promary follicles and seconadry follicles and secondary follicles will have germinal center formation

Metastatic lymph nodes

I hope you understood the difference in appearance of normal lymph node and metastatic lymph node by these images.

These metastatic lymph nodes we need to count and how many they are involved because while giving pTNM staging we have to mention it and any extranodal extension is there or not. These nodes to be removed surgically as they can spread to other nodes also.

References

• Ioachim's Lymph Node Pathology 5th edition