Veterinary Research Forum

Spontaneous primary B cell lymphoblastic lymphoma of the spleen of a 24-month-old male C57BL/6 mouse

Document Type : Clinical Report

Authors

Soo-Eun Sung 1
Minkyoung Sung 1
Kyung-Ku Kang 1
Jae Woo Park 1
Ye-jin Kim 1
Sun Hee Park 2
Duyeol Kim 2
Sijoon Lee 1

1 Preclinical Research Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, South Korea

2 Biotoxtech Co. Ltd., Cheongju, South Korea

10.30466/vrf.2025.2065919.4839
Abstract
Spontaneous lymphoid neoplasms are common among aged C57BL/6 mice, predominantly manifesting as T cell lymphomas. However, primary B cell lymphoblastic lymphomas are rare and poorly characterized, especially in laboratory animals. This case report describes a primary B cell lymphoblastic lymphoma in the spleen of a 24-month-old male C57BL/6 mouse. Gross examination revealed an enlarged spleen with a homogenous, white, firm mass replacing the normal parenchyma. Histopathological analysis revealed that the splenic architecture was diffusely replaced by neoplastic lymphoid cells with high mitotic activity. Immunohistochemical staining confirmed the B cell origin of the neoplasm, demonstrating strong CD20 positivity and CD3 negativity. This case underscores the importance of detailed pathological evaluation in aged laboratory mice, especially to distinguish spontaneous lesions from treatment-induced effects in experimental studies. These findings contribute to the understanding of lymphoid neoplasms in laboratory animals, as well as provide valuable reference data for pre-clinical research in toxicology and oncology.

Keywords

B cell
C57BL/6
Lymphoblastic lymphoma
Mouse
Spleen
Subjects
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Veterinary Research Forum
Volume 17, Issue 7
July 2026
Pages 519-522

  • Receive Date 20 July 2025
  • Revise Date 15 September 2025
  • Accept Date 11 October 2025

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