Diffuse large B-cell lymphoma (DLBCL) in the splenic hilar lymph node mimicking an intrasplenic lesion is considered rare in the literature. This case is discussed as a form of a primary splenic DLBCL and as a stage I/II abdominal DLBCL. Primary splenic DLBCL was previously defined as a lymphoma confined to the spleen, with or without involvement of the hilar lymph node or distant lesions. However, the condition is not included in the 5th edition of the World Health Organization classification. In this report, we describe the case of a 63-year-old Japanese male who presented with a 5 cm ¹⁸F-fluorodeoxyglucose-avid mass identified on imaging, presumed to be an intrasplenic mass. Subsequent splenectomy confirmed that the mass was DLBCL originating from the splenic hilar lymph node, distinctly separated from the spleen and the tail of the pancreas. Postoperatively, the patient responded well to treatment comprising three courses of a combined regimen of polatuzumab vedotin, rituximab, cyclophosphamide, daunorubicin, and prednisolone. This case underscores the importance of caution when diagnosing intrasplenic lesions based on imaging, as the lesions may be located outside the spleen.

1. Coupland SE, Du MQ, Ferry JA, et al. The fifth edition of the WHO classification of mature B-cell neoplasms: Open questions for research. J Pathol. 2024;262(3):255-270. doi: 10.1002/path.6246

2. Shimizu-Kohno K, Kimura Y, Kiyasu J, et al. Malignant lymphoma of the spleen in Japan: A clinicopathological analysis of 115 cases. Pathol Int. 2012;62:577-582. doi: 10.1111/j.1440-1827.2012.02844.x

3. Shimono J, Miyoshi H, Kiyasu J, et al. Clinicopathological analysis of primary splenic diffuse large B-cell lymphoma. Br J Haematol. 2017;178:719-727. doi: 10.1111/bjh.14736

4. Rajendran T, Kini JR, Abna A, Prasad K. Clinical benefit of R-CHOP without splenectomy in stage I primary splenic diffuse large B-cell lymphoma. BMJ Case Rep. 2022;15(1):e246610. doi: 10.1136/bcr-2021-246610

5. Wadsworth PA, Miranda RN, Bhakta P, et al. Primary splenic diffuse large B-cell lymphoma presenting as a splenic abscess. EJHaem. 2023;4:226-231. doi: 10.1002/jha2.642

6. Meng M, Riera CA, Mosquera J, Parikh HR, Singh A. Atypical diffuse large B-cell lymphoma, primary splenic lymphoma variant; A case report. Int J Surg Case Rep. 2023;111:108861. doi: 10.1016/j.ijscr.2023.108861

7. Yonghao Q, Yongyang W, Siqing Y, Lihua C, Shuju T. Comparison of survival outcomes of different treatment modalities for patients with primary splenic diffuse large B cell lymphoma. Ann Hematol. 2023;102(7):1857-1865. doi: 10.1007/s00277-023-05171-z

8. Pirzada S, Hasnain A, Mankani AA, Zahid I. Primary splenic diffuse large b-cell lymphoma: An atypical presentation. Cureus. 2023;15(6):e40793. doi: 10.7759/cureus.40793

9. Neves NM, Lopes AP, Coelho SC, Raimundo A, Mafra MM, Horta AB. Primary splenic diffuse large B-cell lymphoma: A case report. Eur J Case Rep Intern Med. 2023;10(7):003932. doi: 10.12890/2023_003932

10. Seijari MN, Kaspo S, Alshurafa A, Elfaieg A, Sarah A Elkourashy SA. Primary splenic diffuse large B-cell lymphoma: A case report and literature review of a rare condition. Case Rep Oncol. 2024;17(1):447-453. doi: 10.1159/000537780

11. Justo I, Jiménez-Romero C, Suárez A, et al. Case study: Splenic cyst deroofing complicated with B lymphoma. World J Surg Oncol. 2024;22:231. doi: 10.1186/s12957-024-03509-z

12. Abdulbaki R, Tizro P, Nava VE, da Silva MG, Ascensão JL. Low-grade primary splenic CD10-positive small B-cell lymphoma/follicular lymphoma. Curr Oncol. 2021;28(6):4821-4831. doi: 10.3390/curroncol28060407

13. Samuel B, Nalbandyan K, Benharroch D, Levi I. Splenic micronodular T-cell/histiocyte-rich large B-cell lymphoma: The corticosteroid pretreatment hypothesis. Acta Haematol. 2022;145(3):310-317. doi: 10.1159/000520791

14. Tilly H, Morschhauser F, Sehn LH, et al. Polatuzumab vedotin in previously untreated diffuse large B-cell lymphoma. N Engl J Med. 2022;386(4):351-363. doi: 10.1056/NEJMoa2115304

15. Boyer DF, McKelvie PA, de Leval L, et al. Fibrin-associated EBV-positive large B-cell lymphoma: An indolent neoplasm with features distinct from diffuse large B-cell lymphoma associated with chronic inflammation. Am J Surg Pathol. 2017;41:299-312. doi: 10.1097/PAS.0000000000000775

16. Bairey O, Shvidel L, Perry C, et al. Characteristics of primary splenic diffuse large B-cell lymphoma and role of splenectomy in improving survival. Cancer. 2015;121:2909-2916. doi: 10.1002/cncr.29487

17. Persky DO, Li H, Stephens DM, et al. Positron emission tomography-directed therapy for patients with limited-stage diffuse large B-cell lymphoma: Results of intergroup national clinical trials network study S1001. J Clin Oncol. 2020;38(26):3003-3011. doi: 10.1200/JCO.20.00999