Numerous B-cell and T-cell antigens are able to survive fixation and acid decalcification and can be used to
confirm the presence of lymphomatous involvement in routinely processed bone marrow biopsy material.
Although immunophenotyping of lymphoid malignancies in bone marrow sections can be successfully
accomplished, it is always preferable to subtype lymphomas using material from the original involved lymph
node or other primarily affected organ. Bone marrow should, however, be used to subtype cases of
lymphoproliferative disorders which are associated with typical diagnostic findings in this organ (e.g.
hairy cell leukemia), or in the rare cases of primary bone lymphomas.
In most cases all that the hematopathologist needs to determine is whether the lymphomatous proliferation in
the bone marrow is morphologically compatible with the subtype of lymphoma which is known to affect the
patient. In this context, immunohistochemistry can be very helpful by allowing an objective comparison of
the immunophenotype of the malignant cells in the primary affected organ and in the marrow. This is
especially important in cases in which morphology shows discordant cytologic features (e.g. large cell
transformation of B-CLL/SLL). A word of caution: most antibodies reactive with lymphoid antigens in bone
marrow sections are not totally specific. A panel approach based on the use of selected lineage-specific
antibodies is mandatory in the assignation of immunophenotype. The antibodies used in our practice and
their reactivities will be discussed within the framework of the lymphoma subtypes as categorized by the