Histological examinations of the bone lesion biopsy showed plasmacytoma with predominance of
lambda light chain expression in the plasma cell aggregates (Figure 2).
The assignment of
lambda light chain specificity to 8H9 was based upon several independent observations.
Plasma cells infiltration is common in reactive lesion and must be ruled out with staining for kappa or
lambda light chain. In contrast to multiple myeloma, extramedullary plasmacytoma showed absence of cyclin D1 and infrequent expression of CD56.
The immunophenotype conventionally described is the positivity of the tumor cells for HHV8, kappa or
lambda light chains, MUM1, and Ki67 in most cells.
They are characterized by a broad diffuse band with one or more heavy chains and kappa and
lambda light chains. Protein electrophoresis is extremely valuable for recognizing cases of monoclonal gammopathies and for following quantitative changes in spikes.
Flow cytometric analysis showed approximate 1% of total events to be
lambda light chain restricted plasma cells that did not express CD56.
Bone marrow biopsy revealed < 5% of singly disposed mature-appearing CD138+ plasma cells, confirmed to be
lambda light chain restricted by in-situ hybridization; there was no abnormal karyotype on cytogenetic analysis.
Trimolecular complexes of
lambda light chain dimers in serum of a patient with multiple myeloma.
chromosome 8 to chromosome 2, the
lambda light chain.
Caption: FIGURE 7: Liver biopsy stained for
lambda light chain immunoglobulin confirming neoplastic extramedullary plasma cell infiltration from multiple myeloma.
In summary, the patient has a mild plasmacytosis on the biopsy (-5-10%) that is
lambda light chain restricted.
Detection of kappa and
lambda light chain monoclonal proteins in human serum: automated immunoassay versus immunofixation electrophresis.
