This is a difficult case. First- not all monoclonal B cell processes are "Malignant" in that they can spontaneously disappear. We sometimes see them in immunocompromised patients. Also, in some diseases, there is not diagnosis of malignancy until a certain magical number is reached. I have followed a patient with a slowly increasing CD5+ monoclonal B cell population that his oncologist says isn't CLL because the numbers are too low. Someday it will magically become CLL but for now it is just a monoclonal B cell process. In this specific case I think you can report that it is consistent with a monoclonal B cell population. The abnormal brighter cells may have abnormal expression of another antigen which would help you to tease it out further and characterize it. You can site the data on amyloidosis (I like to include more information in weird cases)and I would recommend clinical correlation, evaluation for multiple myeloma/B cell malignancy and close clinical follow up. You are therefore covered. It isn't a clear malignancy but it is monoclonal and the clinicians should fully evaluate the patient and think about the case. Following the patient a little more closely over time may also be useful. I don't think a monoclonal B cell population is ever good- but is it always bad? We don't know. I always talk to the clinicians on cases like these. They appreciate it and you are assured of better communication. Good luck. Maryalice Stetler-Stevenson, M.D., Ph.D. Chief, Flow Cytometry Unit Laboratory of Pathology, NCI, NIH Sometimes you're the windshield, sometimes you're the bug. > ---------- > From: Andrea Illingworth > Sent: Wednesday, April 24, 2002 2:45 PM > To: Cytometry Mailing List > Subject: monoclonal B-cells due to amyloidosis > > Dear group, once again I need your help! > > We recently had a case (left cervical lymph node) which showed a mixture > of 55% T-cells (predominance of CD4) and 45% B-cells. The B-cells were > CD19+, CD20+, CD22+, CD10-, CD5-, CD56-, CD38 weak+ with 15% expressing > kappa and 32% expressing bimodal lambda (abnormal cells appear brighter > positive for lambda). The patient had similar flow findings (reported as > suspicious for LPD/B) about a year with no evidence of lymphoma by > surgical pathology. It was sent out to a consultant who interpreted the > reversed kappa/lambda findings as due to amyloidosis. > I have done some "light" reading on this subject and am still not quite > sure how to report the flow findings. If I understand it correctly, in > primary amyloidosis (the only one associated with plasma cell dyscrasias) > the amyloid is derived from all or a part of a monoclonal Ig light chain. > 20% of patients with amyloidosis have multiple myeloma, the remaining > patients have increased clonal plasma cells but they don't reach 10% in > the bone marrow which is required for a dx of MM. > My questions are: > 1. What exactly does the reversed kappa lambda ratio mean in our case? > That there are monoclonal B-cells somewhere in this patient's body (?MM), > producing the amyloid but since these abnormal cells are not seen in this > particular tissue, we can't call it a LPD/B? In other words, if we find a > monoclonal B-cell population, do we need to check for amyloid first? > 2. Can you see a reversed kappa/lambda ratio in cases other than primary > amyloidosis (secondary and familial)? I know some people might challenge > me on the ratio still being within the normal range but looking at the > histograms, it looks restricted (bimodal expression). > 3. How do we report this out? > > Your help is much appreciated > > Andrea Illingworth, MS, H(ASCP) > Dahl-Chase Flow Cytometry > 333 State Street > Bangor, Maine 04401 >
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