[Foundry738]

"Atypical marrow plasmacytosis" - what's it mean?

by Foundry738 on Mon Oct 23, 2017 4:23 pm

I have a question about bone marrow report terminology versus the terminology used in the diag­nostic criteria for MGUS, smoldering multiple myeloma, and multiple myeloma.

Specifically, the key wording you'll often see for whether or not someone has smoldering multiple myeloma is something like "clonal bone marrow plasma cell percentage that is from 10 to 60 percent" (see, for example, this post here in the forum).

In my bone marrow report, there is the statement: "Atypical marrow plasmacytosis (approxi­mately 10%)".

Does this "atypical marrow plasmacytosis" refer to the same thing as the "clonal bone marrow plasma cell percentage", or something similar but not identical?

Thanks for any help.

[JimNY]

Re: "Atypical marrow plasmacytosis" - what's it mean?

by JimNY on Tue Oct 24, 2017 9:09 am

Strictly speaking, "atypical marrow plasmacytosis" is not the same as having clonal plasma cells in the bone marrow. "Marrow plasmacytosis" just means that more than the normal (expected) amount of plasma cells have been found in the marrow ("plasmacytosis" = "abnormally high level of plasma cells"). "Atypical" could mean there are not-normal plasma cells making up the higher than normal amount of plasma cells, or it could be redundant, reinforcing that plasmacytosis is "atypical".

The key thing about myeloma is that the excess plasma cells in the marrow are not just "atypical" in some way; they are "clonal" (or monoclonal), meaning genetically identical to one another. Normal plasma cells in the marrow are "polyclonal", or genetically diverse.

Practically speaking, it's probably the case that the "atypical marrow plasmacytosis" in your case is due to the presence of clonal plasma cells, and that your "clonal plasma cell percentage" is either 10 percent, or your total (clonal and polyclonal) plasma cell percentage is 10 percent. You'll have to get some clarification, however, whether the excess plasma cells in your marrow are, in fact, clonal, and whether the 10 percent refers to the total plasma cell percentage, or clonal plasma cell percentage.

Good luck, and please update us on what you find out.

[Foundry738]

Re: "Atypical marrow plasmacytosis" - what's it mean?

by Foundry738 on Mon Oct 30, 2017 1:05 pm

Thanks, JimNY. I will pursue the terminology differences and for the moment will stay with biclonal IgG kappa MGUS along with the IgM kappa Waldenstrom's diagnosis that I have.