B-cell lymphomas involving Waldeyer's ring characterized by distinctive clinical and histopathological features: a comparison of pediatric to adult patients

// Lei Chen 1 , Lika’a Fasih Y. Al-Kzayer 2 , Yi Liu 1 , Tingting Liu 3 1 Department of Pathology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China 2 Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Nagano, Japan 3 Department of Pediatric Hematology/Oncology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China Correspondence to: Tingting Liu, email: tingtingliu16@yahoo.co.uk Keywords: B-cell lymphoma, Waldeyer’s ring, MUM1 positive lymphoma Received: April 06, 2016      Accepted: December 16, 2016      Published: January 10, 2017 ABSTRACT B-cell lymphomas involving Waldeyer’s ring (WR) comprise heterogeneous histolopathological subtypes with a wide age range and distinctive clinical features. However, the comparison between pediatric and adult patients is scarce and limited in the literature. Thirty-three cases of B-cell lymphomas involving WR, were collected and evaluated by histolopathological, immunohistochemical and FISH analyses. The 33 cases were categorized into children and adolescents referred as pediatric group ( n = 12), aged (3−19) years and the adult group ( n = 21), aged (20−84) years. The pediatric group included Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) and MUM1-positive-lymphoma in 7, 3 and 2 cases, respectively. While the adult cases comprised of DLBCL, follicular lymphoma, and mucosa associated lymphoid tissue (MALT) lymphoma in 18, 2 and 1 case, respectively. Male gender was predominant in both groups with 3 folds frequency in the pediatric cases compared to 2 folds in the adults counterpart. Pediatric cases showed a significantly higher frequency of stage I disease ( P = 0.019), germinal center B-cell (GCB) phenotype ( P = 0.011), CD10-positive expression ( P = 0.003), and MYC breaks ( P = 0.029) compared to adults. However, MUM1 positive expression was less frequently detected in pediatric patients than adults ( P = 0.082). BCL2 rearrangement was undetectable in both pediatric and adult groups. On the other hand, adult group had the significantly higher proportion of DLBCL ( P < 0.001), BCL2 expression ( P = 0.027) and stage II disease ( P = 0.047) compared to pediatric group. In conclusion, B-cell lymphomas involving WR presented with a wide age range, and evident variation in clinical features, histopathological subtypes and immunophenotypes between pediatric and adult age groups.