Hello everyone, how are you all? I hope you all are doing well and i am too. Today without wasting any time lets dive into learning what is metastasis means. So metastasis means in simple understanding, when a person gets or develops cancer in his body that cancer won't stay within its primary place instead it spread to nearby lymph nodes and structures and this is called metastasis and it is one of the features of malignancy.
For example a person develops tongue- squamous cell carcinoma. Then this squamous cell carcinoma spreads into near by neck lymph nodes and from there it spreads to other organs and making them dysfunctional. Thats why its better to know the status of lymph node and surgeons will remove lymph nodes also to avoid spread and to check lymph nodes whether any lymph node got metastasize.
Now today we are going to see, how we pathologist gets lymph nodes and how we will identify whether a lymph node got metastasized or not.
As a rule of thumb, if we want to know what is abnormal, we have to know what is normal first. Lets discuss it by a clinical scenario.

Case

A man had colon - adenocarcinoma and left hemicolectomy was done and when grossing was done found nearly 18 lymph nodes in the mesentery of colon specimen. They were underwent in tissue processing and staining. Now lets see what we got.....

This is one lymph node showing normal architecture with secondary follicles and germinal center in the cortex. No tumor deposits or metastasis is seen from colon. Below are images you can see that is normal lymph node.

Normal lymph node

Metastatic lymph node

You can see how the architecture of the lymph node was completely distorted and these tumors cells are replacing the normal structures so that it doesnt do its normal function. Here we are not seeing primary or secondary follicles of normal lymph node. This is metastatic lymph node.

Metastatic lymph node or metastasis doesnt mean it has to completely replace the normal structure. Even if you find one very tiny small cluster of tumor cells in the lymph node or other organs then it is considered as metastasis.

Thats why when carcinoma occurs, doctors will remove lymph nodes also and follow the treatment protocol depending upon the pathology report.

I hope you learned something today from my post. I will come with a new medical learning thing.

References

• Robbins & Cotran Pathologic Basis of Disease, 10th Edition
• Mills and Sternberg's Diagnostic Surgical Pathology, (7th Ed.)
• CAP protocol - colon&rectum resection

Thanks for reading,
With regards,