[Blueboar]

Multiple myeloma with no bone marrow involvement?

by Blueboar on Sun Nov 26, 2017 2:21 pm

I have been diagnosed with IgM multiple myeloma, having previously been diagnosed with Waldenstrom's. Two bone marrow biopsies show my bone marrow clear. It has been extensively tested. My IgM is high, but responding to plasmapheresis. The likely source is a mass in my abdomen.

Is it really possible to have multiple myeloma without bone marrow involvement?

[Multibilly]

Re: Multiple myeloma with no bone marrow involvement?

by Multibilly on Mon Nov 27, 2017 9:59 am

Hi Jane,

Sorry to hear about your situation.

First off, it is very rare to have a diagnosis of IgM myeloma.

Technically, in order to have a diagnosis of IgM myeloma, one must have > 10% plasma cell involvement based on a bone marrrow biopsy test. It instead sounds like you have been diagnosed with "clinical" IgM myeloma since the disease isn't showing up in your bone marrow biopsies, but you have some other factors that suggest that diagnosis and rules out Waldenstrom's and POEMS. You may want to read these articles for for more details on diagnosing IgM myeloma:

Schuster, SR, et al, "IgM multiple myeloma: Disease definition, prognosis, and differ­entiation from Waldenstrom's macroglobulinemia," American Journal of Hematology, Nov 2010 (full text of article)

J Mikhael, "Ask the Hematologist: A Diagnostic Approach to Patients with an IgM monoclonal protein", The Hematologist, Sep 15, 2014 (full text of article)

Note that bone marrow biopsies can be hit or miss affairs and may not always catch a pocket of disease when they are performed. I suppose it may be possible that you had two biopsies in a row that hit "dry pockets" both times. But I think it would be pretty unique to have a situation where you have IgM myeloma, yet there is truly no bone marrow involvement whatsoever (but then again, I'm not a doctor, and only a doctor can say this for sure).

Note that lytic lesions in your skeleton and sometimes having translocation t(4;14) as verified by a FISH study are the hallmarks of IgM myeloma. Have you been fully scanned via an MRI or PET/CT for lytic lesions and did your FISH test turn up a t(4;14) translocation?

But what concerns me the most is that you mention a mass in your abdomen (possibly an extramedullary plasmacytoma?) that may be giving off the IgM protein. Have you had this mass biopsied and/or are you receiving treatment (other than plasmapheresis) to address this mass?

[Cheryl G]

Re: Multiple myeloma with no bone marrow involvement?

by Cheryl G on Tue Nov 28, 2017 1:39 pm

Hi Jane,

As usual, Multibilly has given you some great feedback and publications to consult regarding your situation. I would like to add just a few additional comments and suggestions.

One thing I would note is that, as far as I can tell, there is not any distinction between IgM multiple myeloma and, say, IgA or IgG multiple myeloma. This is not the case for MGUS, where IgM MGUS is distinguished from IgA or IgG MGUS. In the case of multiple myeloma, however, the diagnostic criteria put out by the International Myeloma Working Group (IMWG) are the same whether you have an IgM, IgG, IgA, or even IgD or IgE monoclonal protein at diagnosis. Those criteria require that there be biopsy-based evidence that myeloma is present, either in the bone or in tumors outside the bone, and that the myeloma be causing either the classic "CRAB" symptoms, or that there be biomarkers indicating organ damage is very likely in the near future. See these links for more on the diagnostic criteria for multiple myeloma:

• "Criteria for a multiple myeloma diagnosis" (Beacon forum post)
• SV Rajkumar, "New Criteria For The Diagnosis Of Multiple Myeloma And Related Disorders," The Myeloma Beacon, Oct 26, 2014

It sounds from what you wrote that you have at least one plasma cell tumor outside of your bones, but it's not clear whether it's been biopsied. If it in fact is a plasma cell tumor, and you truly have no evidence of monoclonal plasma cells in your bone marrow, then I wonder if the correct diagnosis in your case is a solitary plasmacytoma. The IMWG criteria for a solitary plasmacytoma are:

• Biopsy-proven solitary lesion of bone or soft tissue with evidence of clonal plasma cells
• Normal bone marrow with no evidence of clonal plasma cells
• Normal skeletal survey and MRI (or CT) of spine and pelvis (except for the primary solitary lesion)
• Absence of end-organ damage such as hypercalcemia, renal insufficiency, anemia, or bone lesions (CRAB) that can be attributed to a lymphoplasma cell proliferative disorder

You haven't mentioned what your IgM M-spike was at diagnosis, or what your free light chain levels and ratio were. Those could have played a role in your physician's diagnosis and treat­ment decisions.

Good luck!

[Multibilly]

Re: Multiple myeloma with no bone marrow involvement?

by Multibilly on Tue Nov 28, 2017 2:31 pm

Nice catches Cheryl. The possibility of a solitary plasmacytoma diagnosis is indeed something to consider here. And, to be clear, a biopsy-proven bony or extramedullary plasmacytoma can replace the requirement for > 10% clonal plasma cells to have a diagnosis of multiple myeloma.

[Cheryl G]

Re: Multiple myeloma with no bone marrow involvement?

by Cheryl G on Tue Nov 28, 2017 4:05 pm

Thanks, Multibilly.

As you mention, if there's a bone or extramedullary plasmacytoma that's been proven by biopsy, but a bone marrow biopsy shows no monoclonal plasma cells, you still can have a diagnosis of multiple myeloma. However, that diagnosis is not a given with the presence of a plasmacytoma. There need to be either "CRAB" symptoms, or biomarkers suggesting active disease, for a multiple myeloma diagnosis according to the IMWG criteria.

(I know you realize all this, Multibilly. I just didn't want anyone else reading this thread to think that just because they have a plasmacytoma they automatically have multiple myeloma.)