This study investigated the clinical and pathological profiles of germinal center (GC)-derived diffuse large B-cell lymphomas (DLBCL) with abnormal MUM1 co-expression, focusing on comparisons between pediatric and adult patients. A total of 32 cases showing aberrant MUM1 expression were analyzed, comprising 12 pediatric and 20 adult patients. The lymphomas showed a wide age distribution, affected various anatomical locations, and presented with complex histological and clinical features. Pediatric cases showed a significantly higher incidence of Waldeyer’s ring (WR) involvement (P = 0.008), were more frequently diagnosed at stage II (P = 0.035), and had a lower mortality rate (P = 0.014) compared to adults. The most frequently affected site was the WR, followed by the gastrointestinal tract, lymph nodes, and bone marrow. WR involvement was significantly more prevalent in children than adults (P = 0.008). In adults, lymphomas involving the WR showed clinical staging, outcomes, and pathological patterns similar to pediatric cases. In contrast, while adult cases with gastrointestinal involvement shared clinical characteristics with pediatric presentations, they showed a higher rate of P53 expression. In summary, adult patients with GC-derived DLBCL and aberrant MUM1 expression display more clinical variability than children, although WR involvement in adults parallels pediatric disease features.
