Introduction: Diffuse large B-cell lymphoma (DLBCL) with bone marrow involvement (BMI) indicates poor prognosis. BMI can be assessed by morphology in H&E slide and/or CD20 immunohistochemistry (IHC). This study aims to 1) evaluate the prevalence of BMI in Thammasat university hospital, 2) comparing morphology and CD20 in detection yield of BMI, and 3) correlate tumor volume to IPI score. Method: Retrospective study, 117 bone marrow tissues (staging 111 cases and primary diagnosis 6 cases) from Pathology Laboratory of Thammasat University Hospital from 1 January 2012 to 31 December 2016. Result: BMI was found in 10.8% (12/111 cases) of staging cases and 6 cases of primary diagnosis. H&E had sensitivity 83.3%, specificity 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 98.0% and receiver operating curve (ROC) area 92.0%. Bone marrow tumor volume correlated with IPI-high as 51 - 100% tumor volume had IPI-high in 3/4 cases (75%), 11 - 50% tumor volume had IPI-high in 3/5 cases (60%), and tumor volume 1-10% had IPI-high in 4/8 cases (50%). Conclusions: Prevalence of BMI in DLBCL staging in Thammasat university hospital is slightly lower than previous studies. The detection of tumor cells by morphology in H&E is reliable and maybe unnecessary to stain CD20 in all cases upfront. There is a trend that increasing tumor volume has IPI-high score.
Nintap et al. (Mon,) studied this question.