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🤔Why are splenic metastases so rare?
I always saw the spleen as a lymphoid organ similar to lymph nodes. If the latter are major sites of metastases, why not the former?
Why makes the spleen so inhospitable?
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Conversation
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The relative rarity of splenic metastases was observed in 1888 by Stephen Paget.
He felt this finding could not be due to chance as splenic abscesses weren't all that uncommon.
We'll come back to his preferred explanation later.
sciencedirect.com/science/articl
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An autopsy study of 1,008 patients with metastatic cancer reported the following rates of metastases for two key structures in the lymphatic system:
53%: non-regional lymph nodes
<5%: spleen
Again: why is the spleen spared relative to lymph nodes?
ncbi.nlm.nih.gov/pmc/articles/P
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Many of the earliest explanations offered were anatomic. For example, in 1922 Sappington suggested the following were at play:
➤lack of afferent lymphatics to the spleen
➤sharp angle of the splenic artery
➤rhythmic contractions of the spleen
dx.doi.org/10.1001/jama.1
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But these explanations fail to address the fact that the spleen is one of many areas of the body with apparent protection against metastases. Others include:
➤skeletal muscle
➤thyroid
➤yellow bone marrow
pubmed.ncbi.nlm.nih.gov/33276706/
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Replying to
I have a theory for skeletal muscle and heart, don't have data for thyroid and spleen. Cancer won't do well in tissues that have very strong control of resting potential (and are hyperpolarized a lot): iopscience.iop.org/article/10.108 ; iopscience.iop.org/article/10.108 ;
