Fibrin-associated diffuse large B-cell lymphoma in an ovarian endometriotic cyst: a case report and review of the literature

Background Fibrin-associated diffuse large B-cell lymphoma (FA-DLBCL) is a rare, Epstein–Barr virus (EBV)-positive lymphoma typically occurring in immune-privileged, fibrin-rich environments. It shows an indolent course and is often incidental. While previously reported in thrombi, hematomas, and implants, no cases have been linked to endometriosis. We report the first documented case of FA-DLBCL arising in an ovarian endometriotic cyst. Case presentation A 59-year-old Asian woman with a history of endometriosis presented with progressive abdominal distension. Imaging revealed large cystic ovarian tumors, and bilateral adnexectomy was performed. Intraoperative findings included a 26-cm right ovarian mass comprising two tumors and a 13-cm left ovarian cyst. Histopathology of one right ovarian tumor revealed FA-DLBCL within a fibrin-rich, endometriotic cyst, confirmed by a cluster of differentiation (CD)20, CD30, and Epstein–Barr virus-encoded small RNA in situ hybridization (EBER-ISH) positivity. Serum EBV tests suggested prior infection. The patient remained recurrence-free for 2 years but subsequently developed a pelvic mass with markedly elevated CA 125 levels. Surgical resection revealed metastatic clear cell carcinoma without evidence of recurrent FA-DLBCL, and the patient was diagnosed with stage IIIA1(II) ovarian cancer.

and conclusions This is the first reported case of FA-DLBCL arising within an ovarian endometriotic cyst. FA-DLBCL typically develops in immune-privileged, fibrin-rich, and chronically inflamed environments. Endometriotic cysts share similar characteristics, including hemorrhage, chronic inflammation, and fibrin accumulation, suggesting a permissive microenvironment for EBV-driven lymphomagenesis. In this case, the tumor cells were sparsely distributed within fibrin and difficult to identify, underscoring the diagnostic challenge. Immunohistochemical screening, particularly with CD30 and EBER-ISH, was crucial for diagnosis. The FA-DLBCL component showed no recurrence after surgery; however, the patient later developed ovarian clear cell carcinoma, a known malignancy associated with endometriosis, and died despite treatment. This case underscores the importance of comprehensive histopathological evaluation and vigilant long-term follow-up in patients with endometriotic cysts, as multiple neoplastic processes, including lymphoma and carcinoma, may coexist and influence prognosis. It expands the spectrum of precursor lesions for FA-DLBCL to include endometriotic cysts. Similar content being viewed by others Abbreviations - CA 125: - Cancer antigen 125 - CA 19-9: - Carbohydrate antigen 19-9 - CD: - Cluster of differentiation - CT: - Computed tomography - EBV: - Epstein–Barr virus - EBER-ISH: - Epstein–Barr virus-encoded small RNA in situ hybridization - EC: - Ethics committee - FA-DLBCL: - Fibrin-associated diffuse large B-cell lymphoma - Ig: - Immunoglobulin - VCA: - Virus capsid antigen

We would like to thank Ms. Naoko Tomita for her administrative assistance. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Author information Authors and Affiliations Corresponding author Ethics declarations Ethics approval and consent to participate This case report was approved by the Ethics Committee (EC) of Nihon University on August 25, 2017, with the EC approval number: RK-170711-6. It was conducted in accordance with the principles of the Declaration of Helsinki and CARE reporting guidelines. Written informed consent was obtained from the patient for participation in the study and for the publication of her de-identified data and images. Consent for publication Written informed consent was obtained from the patient during her lifetime for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Competing interests The authors declare that they have no competing interests. Additional information Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary Information Rights and permissions Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. About this article Cite this article Kamata, S., Nishimaki-Watanabe, H., Yamaguchi, H. et al. Fibrin-associated diffuse large B-cell lymphoma in an ovarian endometriotic cyst: a case report and review of the literature. J Med Case Reports (2026). https://doi.org/10.1186/s13256-026-06623-6 Received: Accepted: Published: DOI: https://doi.org/10.1186/s13256-026-06623-6