Role of Immunohistochemistry and Quantitative PCR in Detection of B-Cell Lymphoma Infiltration in Bone Marrow

Abstract

Bone marrow infiltration of malignant lymphoma is essential for staging and prognosis, and could be detected by trephine biopsy. Using routine Hematoxylin and Eosin (HE) staining alone cannot accurately identify infiltration of lymphoma in bone marrow, therefore alternative techniques may be needed. Fifty-three bone marrow biopsies of B-cell lymphoma cases with age ranged from 29 to 74 year-old were included. Lengths of the bone marrow samples were measured and sent for routine HE and immunohistochemistry (IHC) staining. Results were categorized into 3 groups; positive, negative and equivocal. Twenty-three (43%) cases were eligible for quantitative PCR (qPCR) and monoclonal status was determined, based on the expression of kappa and lambda light chains. Bone marrow biopsies of varying lengths (range; 3 to 20 mm) were analyzed. There were no significant differences between patient age and RNA result (p value 0.095) or bone marrow biopsy length and RNA result (p value 0.835). In 18 of 23 cases (78%), the IHC results in concordance with HE result. There were 5 cases showed definitive qPCR results. One case showed equivocal morphology by HE staining but had negative IHC result. Another case showed positive lymphoma infiltration by HE staining but equivocal IHC result. Both cases showed monoclonal qPCR status. There was also another case with both negative HE and IHC staining showed consistent polyclonal qPCR result, as expected. These findings provide evidence that HE and IHC staining alone were not accurate enough to confirm the infiltration of lymphoma in bone marrow. Combinations of multiple diagnostic techniques are necessary to detect minimal infiltration of B-cell lymphoma in bone marrow biopsy. To acquire reliable qPCR results, the use of fresh tissue as resource of sample is recommended.