Germinal Center-Derived Diffuse Large B-cell Lymphomas with Aberrant Co-expression of MUM1 in Adults and Children

The aim of this study is to analyze the clinical and pathological features of germinal center (GC)-derived diffuse large B-cell lymphomas (DLBCL) with aberrant co-expression of MUM1 and to further analyze the differences between adults and pediatric populations.  Clinical and pathological data of 32 cases of GC-derived DLBCL with aberrant co-expression of MUM1 were reviewed and analyzed. Thirty-two cases were categorized into pediatric (n=12) and adult (n=20) groups. GC-derived DLBCL with aberrant co-expression of MUM1 was found to manifest a wide age range, extensive involvement sites, different histopathological distribution, and complex clinical presentations. Compared to adults, pediatric patients showed a significantly higher frequency of Waldeyer's ring (WR) involvement (P=0.008), higher frequency of stage II (P=0.035), and lower incidence of fatality (P=0.014).  Among the 32 cases, lymphomas were frequently involved in WR, followed by the gastrointestinal tract, lymph nodes, and bone marrow. Pediatric patients showed a significantly higher frequency of WR involvement than adult patients (P=0.008). Lymphomas involving WR in adults showed similar localized clinical stages, excellent outcomes, and pathological features compared to the disease in the pediatric population. Lymphomas involving the gastrointestinal tract in adults shared clinical features with the disease in children but with high P53 positive expression. GC-derived DLBCL with aberrant co-expression of MUM1 in adults is clinically more heterogeneous than children. Tumors involving WR in adults share many similarities to their pediatric counterparts.