I just had an extraordinary experience with kappa and lambda light
chain staining, or rather the lack thereof. I didn't get to see the
IHC slides, which were prepared at a reference laboratory (well, to
give them due credit, by Vanderbilt's hematopathology division).
I saw an odd-looking lymphoma in an older woman, and sent the material
to Vanderbilt for immunostains. (Unfortunately I could not prepare
imprints or obtain flow cytometry, since I received the specimen
already in formalin.) Vandy did the necessary immunostains, and could
not see either kappa and lambda marking. IHC for IgG heavy chain was
however positive. Cells showing plasmacytoid differentiation marked
for CD138, while more lymphocyte-like tumor cells marked for CD20 and
other B-cell markers.
Their diagnosis of gamma heavy chain disease was borne out by
subsequent serum protein studies (I haven't seen those reports.)
Apparently they tumbled to the diagnosis because of the lack of light
chain marking in a tumor that seemed obviously clonal. Impressive!
(Furthermore, Vandy's favored to kick UT's butt a week from Saturday.)
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