Should plasmacytomas be biopsied and tested genetically?

[Music] should plasmacytomas be biopsied and tested genetically this is a clinical question i guess i would make the argument that wherever the plasma cell is proliferating and if it's proliferating at different locations so you've got a bone marrow where there's plasma cells but now if you have a solid tumor like a plasmacytoma i would still argue that you want to test that particular site because there's no assurance that the plasmacytoma has all of the same genetic mutations and variations as the tumor that's in the bone marrow the word plasmacytoma has many connotations so the more imaging we do the more we realize that myeloma is a lumpy bumpy disease a lot of patients have solid foci of disease in the bone bone marrow we call them focal lesions a plasmacytoma tends to imply a lesion at a specific site that's grown to form a tumor and often there's a differential diagnosis problem so is it myeloma is it a plasmacytoma is it a sarcoma or is it another type of metastasis to bone you need to have the biopsy to see the plasma cells characterize them to know what you're dealing with because it turns out plasmocytomas are quite sensitive to radiation and so you could be internally fixed irradiated stabilized and then you can get on and treat the rest of the disease throughout your body some people have isolated plasmacytomas and if they're small and you do an mrd test somewhere else in the body and there's no cells there maybe you could just get away with treating it locally a question that comes up is whether one should biopsy a plasmacytoma in a person who has a history of of multiple myeloma and and there's two aspects to this there's the academic aspect we know that there could be genetic differences in that plasmacytoma that may not be present in the remainder of the cells in the bone marrow but one challenge to that is that even if you do that what if you biopsy in a site that doesn't have that change were you to biopsy ten times or were you better off maybe getting more and more samples or even sampling more plasmacytomas so i think practically it's not that important unless something happens that the patient is not responding to the treatment so in my practice i don't do repeat biopsies of plasmocytomas often unless something is happening that makes us worry that we're not seeing the expected behavior and that could be either growth of the plasmacytoma because somehow it's being refractory to the to the drugs being used and that is possible because sometimes plasma cytomas may be areas with slightly more advanced myeloma cells more clonally advanced we can sometimes see and i've seen a few times in my practice too that the plasmocytomas they can start depositing proteins amyloid-like proteins and they may grow they may even have symptoms and pain because of this so so that may be another reason why something may not go in the direction we think it should be going and we can sometimes use plasmocytomas also to gauge response to treatment so we have a person who has multiple plasmacytomas and we start therapy it's something visual that we can see that the medications are working