Fibrin-associated diffuse large B-cell lymphoma (fibrin-associated DLBCL) is a very rare subtype of Epstein-Barr virus (EBV)-associated DLBCL that usually develops within fibrin-rich lesions such as cardiac myxoma, chronic hematoma, thrombus, pseudocysts or cysts, prosthetic devices or breast implants. The pathogenesis as well as the clinicopathologic features of this usually indolent lymphoproliferative disorder, which are based on the analysis of a relatively limited number of cases, are still poorly known. Herein, we report a case of fibrin-associated DLBCL that was incidentally found within a multinodular goiter, a location not yet reported to our knowledge. Our findings not only illustrate further the specific nature of this peculiar lymphoproliferative disorder but also allow some interesting comments on its pathogenesis.

1. Chan, JKC, Aozasa, K, Gaulard, P, et al. Diffuse large B-cell lymphoma associated with chronic inflammation. In: Swerdlow, SH, Campo, E, Harris, NL, eds. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. IARC Press; 2017:309-311.
Google Scholar2. Boroumand, N, Ly, TL, Sonstein, J, Medeiros, LJ. Microscopic diffuse large B-cell lymphoma (DLBCL) occurring in pseudocysts. Do these tumors belong to the category of DLBCL associated with chronic inflammation? Am J Surg Pathol. 2012;36(7):1074-1080.
Google Scholar | Crossref | Medline3. 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(3):299-312.
Google Scholar | Crossref | Medline4. Natkunam, Y, Goodlad, JR, Chadburn, A, et al. EBV-positive B-cell proliferations of varied malignant potential. 2015 SH/EAHP workshop report - part 1. Am J Clin Pathol. 2017;147(2):129-152.
Google Scholar | Crossref | Medline5. de Leval, L, Copie-Bergman, C, Rosenwald, A, et al. B cell lymphomas with discordance between pathological features and clinical behavior. Virchows Arch. 2017;471(4):439-451.
Google Scholar | Crossref | Medline6. Dojcinov, SD, Fend, F, Quintanilla-Martinez, L. EBV-positive lymphoproliferations of B- T- and NK-cell derivation in non-immunocompromised hosts. Pathogens. 2018;7(1):28. doi: 10.3390/pathogens7010028
Google Scholar | Crossref7. King, RL, Goodlad, JR, Calaminici, M, et al. Lymphomas arising in immune-privileged sites: insights into biology, diagnosis, and pathogenesis. Virchows Arch. 2020;476(5):647-665.
Google Scholar | Crossref | Medline8. Derringer, GA, Thompson, LD, Frommelt, RA, Bijwaard, KE, Heffess, CS, Abbondanzo, SL. Malignant lymphoma of the thyroid gland: a clinicopathologic study of 108 cases. Am J Surg Pathol. 2000;24(5):623-639.
Google Scholar | Crossref | Medline9. Skacel, M, Ross, CW, Hsi, ED. A reassessment of primary thyroid lymphoma: high-grade MALT-type lymphoma as a distinct subtype of diffuse large B-cell lymphoma. Histopathology. 2000;37(1):10-18.
Google Scholar | Crossref | Medline10. WHO Classification of Tumours. https://whobluebooks.iarc.fr/structures/haematolymphoid/
Google Scholar