Peripheral blood abnormalities and bone marrow infiltration in canine large B‐cell lymphoma: is there a link?

Abstract

Official guidelines do not consider bone marrow (BM) assessment mandatory in staging canine lymphoma unless blood cytopenias are present. The aim of this study was to find out if blood abnormalities can predict marrow involvement in canine large B-cell lymphoma. BM infiltration was assessed via flow cytometry. No difference was found between dogs without haematological abnormalities and dogs with at least one. However, the degree of infiltration was significantly higher in dogs with thrombocytopenia, leucocytosis or lymphocytosis and was negatively correlated to platelet count and positively to blood infiltration. Our results suggest that blood abnormalities are not always predictive of marrow involvement, even if thrombocytopenia, leucocytosis or lymphocytosis could suggest a higher infiltration. BM evaluation should therefore be included in routine staging in order not to miss infiltrated samples and to improve classification. However, its clinical relevance and prognostic value are still not defined and further studies are needed.

Hematologic findings predictive of bone marrow disease in dogs with multicentric large‐cell lymphoma

“…Interestingly, 50% of the dogs with bone marrow involvement (with < 5% to > 20% neoplastic lymphocytes) lacked hematologic abnormalities, such as thrombocytopenia, leukocytosis, or lymphocytosis. In agreement with our results, these authors found that bone marrow disease was also present in dogs without hematologic abnormalities, suggesting that bone marrow evaluation should be included in routine staging . Strategies for evaluating bone marrow disease in human patients with lymphoma are still evolving .…”

“…The implementation of more sensitive tests such as flow cytometry would probably improve the ability of detecting neoplastic cells. A recent study used flow cytometry of blood and bone marrow samples to determine the presence of neoplastic cells in dogs with large B‐cell lymphoma . Interestingly, 50% of the dogs with bone marrow involvement (with < 5% to > 20% neoplastic lymphocytes) lacked hematologic abnormalities, such as thrombocytopenia, leukocytosis, or lymphocytosis.…”

Analytical and diagnostic validation of a flow cytometric strategy to quantify blood and marrow infiltration in dogs with large B‐cell lymphoma

“…However, this proportional error has only a tenuous clinical relevance, since it affects only high infiltration values, which are uncommon in canine LBCL (11,12) and far from the prognostically relevant cut-off of 3% (11). Indeed, only a slight proportional error in BM dilutions was found.…”

“…Although causes for this slight error are not neat to the authors, this may be associated to preanalytical factors, such as manual dilutions preparation, or to the presence of stromal or adipose cells either in the LN or in the BM sample that were counted by the hematology analyzer but were not included in the FC gates. However, this proportional error has only a tenuous clinical relevance, since it affects only high infiltration values, which are uncommon in canine LBCL (11,12) and far from the prognostically relevant cut-off of 3% (11).…”

“…In this contest, peripheral blood (PB) and bone marrow (BM) infiltration have been assessed alternatively by cytology (5)(6)(7)(8), flow cytometry (FC; (9)(10)(11)(12)) or PCR for antigen receptor rearrangements (PARR) (13), but only FC has been demonstrated to have a prognostic relevance in dogs with large B-cell lymphoma (LBCL) (11). PB and BM infiltration were quantified as the percentage of large B-cells on the total CD45-positive cells.…”