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Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report

Received: 26 November 2025     Accepted: 12 December 2025     Published: 31 December 2025
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Abstract

Aromatase inhibitors (AIs) are the standard adjuvant therapy for hormone-receptor–positive breast cancer in postmenopausal women and are considered less thrombogenic than tamoxifen. However, rare autoimmune complications, including lupus-like syndromes, inflammatory arthritis, and hepatitis, have been described. Antiphospholipid syndrome (APS), an autoimmune prothrombotic disorder is exceedingly rare in patients taking aromatase inhibitors. We present the case of a 68-year-old woman with breast cancer treated with surgery, chemotherapy, and letrozole for 3 years who subsequently developed deep venous thrombosis, ischemic stroke, severe thrombocytopenia, severe gastrointestinal bleeding, and triple-positive antiphospholipid antibody profile consistent with primary APS. Laboratory and imaging work-up excluded secondary causes of thrombosis such as systemic lupus erythematosus, bone marrow disease, metastatic cancer and heparin-induced thrombocytopenia. Her course was further complicated by refractory gastrointestinal bleeding which continued even after discontinuation of low-molecular-weight heparin (LMWH). Bleeding resolved only after argon plasma coagulation (APC). Because of ongoing thrombosis risk, anticoagulation was transitioned from LMWH to warfarin, and hydroxychloroquine was initiated, resulting in platelet stabilization (23 → 145 × 109/L). She had no further bleeding, and no recurrent thrombotic events. This case presents the clinical course, diagnostic work-up, and management of primary APS emerging during prolonged aromatase inhibitor therapy and summarizes relevant considerations for evaluation of thrombosis and thrombocytopenia in patients treated with endocrine therapy for breast cancer.

Published in American Journal of Internal Medicine (Volume 13, Issue 6)
DOI 10.11648/j.ajim.20251306.11
Page(s) 89-94
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Antiphospholipid Syndrome, Aromatase Inhibitor, Letrozole, Thrombocytopenia, Argon Plasma Coagulation, Warfarin, Hydroxychloroquine, Breast Cancer

References
[1] Miyakis S, et al. J Thromb Haemost. 2006; 4: 295–306.
[2] Tektonidou MG, et al. Ann Rheum Dis. 2019; 78: 1296–1304.
[3] Ordi-Ros J, et al. Ann Intern Med. 2019; 171: 685–694.
[4] Lazzaroni M G, et al. Front Immunol. 2019; 10: 1996.
[5] Straub R H. Endocr Rev. 2007; 28: 521–574
[6] Matthews A, et al. BMJ. 2018; 363: k3845.
[7] Trancart M, et al. Br J Dermatol. 2008; 158: 628–629.
[8] Bao T, et al. Breast Cancer Res Treat. 2010; 121: 789–791.
[9] Wahl DG, et al. Br J Haematol. 2020; 189: 212–223.
[10] Pierangeli SS, et al. Immune pathways in APS. Autoimmun Rev. 2011.
Cite This Article
  • APA Style

    Dhamo, B., Tozharaku, R., Gashi, V., Ramaj, O., Rista, E., et al. (2025). Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report. American Journal of Internal Medicine, 13(6), 89-94. https://doi.org/10.11648/j.ajim.20251306.11

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    ACS Style

    Dhamo, B.; Tozharaku, R.; Gashi, V.; Ramaj, O.; Rista, E., et al. Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report. Am. J. Intern. Med. 2025, 13(6), 89-94. doi: 10.11648/j.ajim.20251306.11

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    AMA Style

    Dhamo B, Tozharaku R, Gashi V, Ramaj O, Rista E, et al. Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report. Am J Intern Med. 2025;13(6):89-94. doi: 10.11648/j.ajim.20251306.11

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  • @article{10.11648/j.ajim.20251306.11,
      author = {Blerina Dhamo and Resmije Tozharaku and Valbona Gashi and Olta Ramaj and Elvana Rista and Blerim Arapi},
      title = {Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report},
      journal = {American Journal of Internal Medicine},
      volume = {13},
      number = {6},
      pages = {89-94},
      doi = {10.11648/j.ajim.20251306.11},
      url = {https://doi.org/10.11648/j.ajim.20251306.11},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajim.20251306.11},
      abstract = {Aromatase inhibitors (AIs) are the standard adjuvant therapy for hormone-receptor–positive breast cancer in postmenopausal women and are considered less thrombogenic than tamoxifen. However, rare autoimmune complications, including lupus-like syndromes, inflammatory arthritis, and hepatitis, have been described. Antiphospholipid syndrome (APS), an autoimmune prothrombotic disorder is exceedingly rare in patients taking aromatase inhibitors. We present the case of a 68-year-old woman with breast cancer treated with surgery, chemotherapy, and letrozole for 3 years who subsequently developed deep venous thrombosis, ischemic stroke, severe thrombocytopenia, severe gastrointestinal bleeding, and triple-positive antiphospholipid antibody profile consistent with primary APS. Laboratory and imaging work-up excluded secondary causes of thrombosis such as systemic lupus erythematosus, bone marrow disease, metastatic cancer and heparin-induced thrombocytopenia. Her course was further complicated by refractory gastrointestinal bleeding which continued even after discontinuation of low-molecular-weight heparin (LMWH). Bleeding resolved only after argon plasma coagulation (APC). Because of ongoing thrombosis risk, anticoagulation was transitioned from LMWH to warfarin, and hydroxychloroquine was initiated, resulting in platelet stabilization (23 → 145 × 109/L). She had no further bleeding, and no recurrent thrombotic events. This case presents the clinical course, diagnostic work-up, and management of primary APS emerging during prolonged aromatase inhibitor therapy and summarizes relevant considerations for evaluation of thrombosis and thrombocytopenia in patients treated with endocrine therapy for breast cancer.},
     year = {2025}
    }
    

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  • TY  - JOUR
    T1  - Primary Antiphospholipid Syndrome Emerging During Long-term Aromatase Inhibitor Therapy: A Clinical Case Report
    AU  - Blerina Dhamo
    AU  - Resmije Tozharaku
    AU  - Valbona Gashi
    AU  - Olta Ramaj
    AU  - Elvana Rista
    AU  - Blerim Arapi
    Y1  - 2025/12/31
    PY  - 2025
    N1  - https://doi.org/10.11648/j.ajim.20251306.11
    DO  - 10.11648/j.ajim.20251306.11
    T2  - American Journal of Internal Medicine
    JF  - American Journal of Internal Medicine
    JO  - American Journal of Internal Medicine
    SP  - 89
    EP  - 94
    PB  - Science Publishing Group
    SN  - 2330-4324
    UR  - https://doi.org/10.11648/j.ajim.20251306.11
    AB  - Aromatase inhibitors (AIs) are the standard adjuvant therapy for hormone-receptor–positive breast cancer in postmenopausal women and are considered less thrombogenic than tamoxifen. However, rare autoimmune complications, including lupus-like syndromes, inflammatory arthritis, and hepatitis, have been described. Antiphospholipid syndrome (APS), an autoimmune prothrombotic disorder is exceedingly rare in patients taking aromatase inhibitors. We present the case of a 68-year-old woman with breast cancer treated with surgery, chemotherapy, and letrozole for 3 years who subsequently developed deep venous thrombosis, ischemic stroke, severe thrombocytopenia, severe gastrointestinal bleeding, and triple-positive antiphospholipid antibody profile consistent with primary APS. Laboratory and imaging work-up excluded secondary causes of thrombosis such as systemic lupus erythematosus, bone marrow disease, metastatic cancer and heparin-induced thrombocytopenia. Her course was further complicated by refractory gastrointestinal bleeding which continued even after discontinuation of low-molecular-weight heparin (LMWH). Bleeding resolved only after argon plasma coagulation (APC). Because of ongoing thrombosis risk, anticoagulation was transitioned from LMWH to warfarin, and hydroxychloroquine was initiated, resulting in platelet stabilization (23 → 145 × 109/L). She had no further bleeding, and no recurrent thrombotic events. This case presents the clinical course, diagnostic work-up, and management of primary APS emerging during prolonged aromatase inhibitor therapy and summarizes relevant considerations for evaluation of thrombosis and thrombocytopenia in patients treated with endocrine therapy for breast cancer.
    VL  - 13
    IS  - 6
    ER  - 

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Author Information
  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

  • Internal Medicine Service, Hygeia Hospital, Tirana, Albania

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