Spandidos Publications Logo
  • About
    • About Spandidos
    • Aims and Scopes
    • Abstracting and Indexing
    • Editorial Policies
    • Reprints and Permissions
    • Job Opportunities
    • Terms and Conditions
    • Contact
  • Journals
    • All Journals
    • Oncology Letters
      • Oncology Letters
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Oncology
      • International Journal of Oncology
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Molecular and Clinical Oncology
      • Molecular and Clinical Oncology
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Experimental and Therapeutic Medicine
      • Experimental and Therapeutic Medicine
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Molecular Medicine
      • International Journal of Molecular Medicine
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Biomedical Reports
      • Biomedical Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Oncology Reports
      • Oncology Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Molecular Medicine Reports
      • Molecular Medicine Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • World Academy of Sciences Journal
      • World Academy of Sciences Journal
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Functional Nutrition
      • International Journal of Functional Nutrition
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Epigenetics
      • International Journal of Epigenetics
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Medicine International
      • Medicine International
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
  • Articles
  • Information
    • Information for Authors
    • Information for Reviewers
    • Information for Librarians
    • Information for Advertisers
    • Conferences
  • Language Editing
Spandidos Publications Logo
  • About
    • About Spandidos
    • Aims and Scopes
    • Abstracting and Indexing
    • Editorial Policies
    • Reprints and Permissions
    • Job Opportunities
    • Terms and Conditions
    • Contact
  • Journals
    • All Journals
    • Biomedical Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Experimental and Therapeutic Medicine
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Epigenetics
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Functional Nutrition
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Molecular Medicine
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • International Journal of Oncology
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Medicine International
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Molecular and Clinical Oncology
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Molecular Medicine Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Oncology Letters
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • Oncology Reports
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
    • World Academy of Sciences Journal
      • Information for Authors
      • Editorial Policies
      • Editorial Board
      • Aims and Scope
      • Abstracting and Indexing
      • Bibliographic Information
      • Archive
  • Articles
  • Information
    • For Authors
    • For Reviewers
    • For Librarians
    • For Advertisers
    • Conferences
  • Language Editing
Login Register Submit
  • This site uses cookies
  • You can change your cookie settings at any time by following the instructions in our Cookie Policy. To find out more, you may read our Privacy Policy.

    I agree
Search articles by DOI, keyword, author or affiliation
Search
Advanced Search
presentation
Oncology Letters
Join Editorial Board Propose a Special Issue
Print ISSN: 1792-1074 Online ISSN: 1792-1082
Journal Cover
April-2026 Volume 31 Issue 4

Full Size Image

Sign up for eToc alerts
Recommend to Library

Journals

International Journal of Molecular Medicine

International Journal of Molecular Medicine

International Journal of Molecular Medicine is an international journal devoted to molecular mechanisms of human disease.

International Journal of Oncology

International Journal of Oncology

International Journal of Oncology is an international journal devoted to oncology research and cancer treatment.

Molecular Medicine Reports

Molecular Medicine Reports

Covers molecular medicine topics such as pharmacology, pathology, genetics, neuroscience, infectious diseases, molecular cardiology, and molecular surgery.

Oncology Reports

Oncology Reports

Oncology Reports is an international journal devoted to fundamental and applied research in Oncology.

Experimental and Therapeutic Medicine

Experimental and Therapeutic Medicine

Experimental and Therapeutic Medicine is an international journal devoted to laboratory and clinical medicine.

Oncology Letters

Oncology Letters

Oncology Letters is an international journal devoted to Experimental and Clinical Oncology.

Biomedical Reports

Biomedical Reports

Explores a wide range of biological and medical fields, including pharmacology, genetics, microbiology, neuroscience, and molecular cardiology.

Molecular and Clinical Oncology

Molecular and Clinical Oncology

International journal addressing all aspects of oncology research, from tumorigenesis and oncogenes to chemotherapy and metastasis.

World Academy of Sciences Journal

World Academy of Sciences Journal

Multidisciplinary open-access journal spanning biochemistry, genetics, neuroscience, environmental health, and synthetic biology.

International Journal of Functional Nutrition

International Journal of Functional Nutrition

Open-access journal combining biochemistry, pharmacology, immunology, and genetics to advance health through functional nutrition.

International Journal of Epigenetics

International Journal of Epigenetics

Publishes open-access research on using epigenetics to advance understanding and treatment of human disease.

Medicine International

Medicine International

An International Open Access Journal Devoted to General Medicine.

Journal Cover
April-2026 Volume 31 Issue 4

Full Size Image

Sign up for eToc alerts
Recommend to Library

  • Article
  • Citations
    • Cite This Article
    • Download Citation
    • Create Citation Alert
    • Remove Citation Alert
    • Cited By
  • Similar Articles
    • Related Articles (in Spandidos Publications)
    • Similar Articles (Google Scholar)
    • Similar Articles (PubMed)
  • Download PDF
  • Download XML
  • View XML
Case Report Open Access

Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report

  • Authors:
    • Tomoki Nakagawa
    • Naohiro Aruga
    • Hajime Watanabe
    • Ryota Masuda
    • Shunsuke Yamada
    • Masayuki Iwazaki
  • View Affiliations / Copyright

    Affiliations: Department of Thoracic Surgery, Tokai University Hachioji Hospital, Hachioji, Tokyo 192‑0032, Japan, Department of Thoracic Surgery, Department of Surgery, Tokai University School of Medicine, Isehara, Kanagawa 259‑1143, Japan
    Copyright: © Nakagawa et al. This is an open access article distributed under the terms of Creative Commons Attribution License.
  • Article Number: 121
    |
    Published online on: January 29, 2026
       https://doi.org/10.3892/ol.2026.15474
  • Expand metrics +
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Metrics: Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )
Cited By (CrossRef): 0 citations Loading Articles...

This article is mentioned in:


Abstract

Microsatellite instability‑high (MSI‑H) tumors, which exhibit somatic hypermutations due to defects in the DNA mismatch repair system, are found in several cancer types. These tumors are known for their responsiveness to immune checkpoint inhibitors (ICIs), regardless of tumor origin. Thymic carcinomas (TCs) are characterized by high programmed death ligand 1 expression and low levels of somatic mutations. Consequently, the incidence of MSI‑H TCs is extremely rare. To the best of our knowledge, the present report is the first to describe a case of recurrent MSI‑H TC achieving complete remission with pembrolizumab monotherapy, distinguishing it from prior reports of partial responses. The patient in the present case was a 78‑year‑old woman with solitary pulmonary and thymic tumors. Thymoma, lung cancer or breast cancer with lung metastasis were suspected, and simultaneous videoscopic resection was performed. The patient was diagnosed with TC with pulmonary metastasis. Adjuvant platinum‑based doublet chemotherapy was only administered twice due to side effects, and extensive recurrent lesions were found in the thoracic cavity 8 months after surgery. Genetic testing of the tumor tissue revealed MSI‑H, and pembrolizumab was administered as second‑line chemotherapy. A total of 4 years and 9 months after the initial surgery, the metastatic lesions had completely disappeared, with no signs of recurrence. In conclusion, the present report describes a rare case of recurrent TC presenting with MSI‑H, in which a complete remission was achieved with immune checkpoint inhibitor (ICI) treatment; however, further research is needed to explore the efficacy of ICIs in rare cases of MSI‑H TCs.

View Figures

Figure 1

Preoperative CT. CT images show (A)
anterior mediastinal tumor and (B) pulmonary nodule. CT, computed
tomography.

Figure 2

Histological and positive
immunohistochemical findings of the anterior mediastinal tumor. (A)
Low power view reveals that the tumor is surrounded by a fibrous
capsule but shows focal invasion to the fat tissue beyond the
capsule. (B) High power view demonstrates that the tumor with
necrosis was composed of epithelial cells showing marked
pleomorphism and frequent mitosis. The arrows highlight the regions
with the highest degree of cellular atypia. Immunohistochemically,
the tumor cells were focal positive for (C) keratin AE1/3 and (D)
p63, suggesting an epithelial origin.

Figure 3

Negative immunohistochemical findings
of the anterior mediastinal tumor. Tumor cells were negative for
(A) CD5, (B) C-kit, (C) TTF-1, (D) CEA and (E) MART-1. TTF-1,
thyroid transcription factor-1; CEA, carcinoembryonic antigen;
MART-1, melanoma antigen recognized by T cells.

Figure 4

Effect of immune checkpoint inhibitors
on recurrent lesions. Serial CT images demonstrate gradual
shrinkage and complete disappearance of the largest pulmonary
lesion over the course of 20 doses of pembrolizumab. (A) POD 237
showing the recurrent pulmonary lesion. (B) POD 335 showing the
lesion after 4 doses of pembrolizumab. (C) POD 671 showing the
lesion after 16 doses. (D) POD 895 showing the complete
disappearance of the lesion. POD, postoperative day.

Figure 5

Timeline of ICI therapy and tumor
response with corresponding CT findings. ICI, immune checkpoint
inhibiter; CT, computed tomography.

Figure 6

Pedigree chart of the proband with
microsatellite instability-high thymic carcinoma. No family history
of Lynch syndrome associated tumor was identified.
View References

1 

Lorenzi M, Amonkar M, Zhang J, Mehta S and Liaw KL: Epidemiology of microsatellite instability-high (MSI-H) and deficient mismatch repair (dMMR) in solid tumors: A structured literature review. J Oncol. 2020:18079292020. View Article : Google Scholar

2 

Marabelle A, Le DT, Ascierto PA, Di Giacomo AM, De Jesus-Acosta A, Delord JP, Geva R, Gottfried M, Penel N, Hansen AR, et al: Efficacy of pembrolizumab in patients with noncolorectal high microsatellite instability/mismatch repair-deficient cancer: Results from the phase II KEYNOTE-158 study. J Clin Oncol. 38:1–10. 2020. View Article : Google Scholar : PubMed/NCBI

3 

Okuma Y: Prospects for thymic carcinoma treatment. Haigan. 64:821–827. 2024. View Article : Google Scholar

4 

Koizumi T, Otsuki K, Tanaka Y, Noguchi T, Fukushuima T, Kobayashi T, Takesumi O, Sekiguchi N and Hamanaka K: National incidence and initial therapy for thymic carcinoma in Japan: Based on analysis of hospital-based cancer registry data, 2009–2015. Jpn J Clin Oncol. 50:434–439. 2020. View Article : Google Scholar : PubMed/NCBI

5 

Bakhos CT, Salami AC, Kaiser LR, Petrov RV and Abbas AE: Thymic neuroendocrine tumors and thymic carcinoma: Demographics, treatment, and survival. Innovations (Phila). 15:468–474. 2020. View Article : Google Scholar : PubMed/NCBI

6 

Hirai F, Yamanaka T, Taguchi K, Daga H, Ono A, Tanaka K, Kogure Y, Shimizu J, Kimura T, Fukuoka J, et al: A multicenter phase II study of carboplatin and paclitaxel for advanced thymic carcinoma: WJOG4207L. Ann Oncol. 26:363–368. 2015. View Article : Google Scholar : PubMed/NCBI

7 

Sato J, Satouchi M, Itoh S, Okuma Y, Niho S, Mizugaki H, Murakami H, Fujisaka Y, Kozuki T, Nakamura K, et al: Lenvatinib in patients with advanced or metastatic thymic carcinoma (REMORA): A multicentre, phase 2 trial. Lancer Oncol. 21:843–850. 2020. View Article : Google Scholar

8 

Cho J, Kim HS, Ku BM, Choi YL, Cristescu R, Han J, Sun JM, Lee SH, Ahn JS, Park K and Ahn MJ: Pembrolizumab for patients with refractory or relapsed thymic epithelial Tumor: An open-label phase II trial. J Clin Oncol. 37:2162–2170. 2019. View Article : Google Scholar : PubMed/NCBI

9 

Giaccone G, Kim C, Thompson J, McGuire C, Kallakury B, Chahine JJ, Maning M, Mogg R, Blumenschein WM, Tan MT, et al: Pembrolizumab in patients with thymic carcinoma: A single-arm, single-centre, phase 2 study. Lancet Oncol. 19:347–355. 2018. View Article : Google Scholar : PubMed/NCBI

10 

Yokoyama S and Miyoshi T: Thymic tumors and immune checkpoint inhibutors. J Thorac Dis. 10:S1509–S1515. 2018. View Article : Google Scholar : PubMed/NCBI

11 

Akagi K, Oki E, Taniguchi H, Nakatani K, Aoki D, Kuawata T and Yoahino T: Real-world data on microsatellite instability status in various unresectable or metastatic solid tumors. Cancer Sci. 112:1105–1113. 2021. View Article : Google Scholar : PubMed/NCBI

12 

Repetto M, Conforti F, Pirola S, Calvello M, Pala L, Bonanni B, Catania C, Curigliano G and De Pas T: Thymic carcinoma with Lynch syndrome or microsatellite instability, a rare entity responsive to immunotherapy. Eur J Cancer. 153:162–167. 2021. View Article : Google Scholar : PubMed/NCBI

13 

Watanabe M, Tanakaya K, Furukawa S, Shiotani T, Sato Y, Taniguchi F, Kanaya N, Aoki H, Sugano K, Ishida H, et al: Two cases of thymic cancer in patients with Lynch syndrome. Intern Med. 62:649–653. 2023. View Article : Google Scholar : PubMed/NCBI

14 

Yanagihara T, Kawamura T, Maki N, Kobayashi N, Kikuchi S, Goto Y, Ichimura H and Sato Y: Practical methods to differentiate thymic malignancies. Surg Today. 54:899–906. 2024. View Article : Google Scholar : PubMed/NCBI

15 

Igai H, Matsuura N, Tarumi S, Chang SS, Misaki N, Go T, Ishikawa S and Yokomise H: Usefulness of [18F]fluoro-2-deoxy-D-glucose positron emission tomography for predicting the World Health Organization malignancy grade of thymic epithelial tumors. Eur J Cardiothorac Surg. 40:143–145. 2011. View Article : Google Scholar : PubMed/NCBI

16 

Brierley JD, Gospodarowicz MK and Wittekind C: TNM classification of malignant tumours. 8th edition. Wiley-Blackwell; Oxford: pp. 114–124. 2017

17 

Masaoka A, Monden Y, Nakahara K and Tanioka T: Follow-up study of thymomas with special reference to their clinical stages. Cancer. 48:2485–2492. 1981. View Article : Google Scholar : PubMed/NCBI

18 

Pharmaceuticals and Medical Devices Agency, . KEYTRUDA® Intravenous Infusion 100 mg: Package Insert. Version 25. https://www.pmda.go.jp/PmdaSearch/bookSearch/01/14987185809730Accessed (In Japanese). September 20–2025

19 

Pharmaceutical Evaluation Division, Pharmaceutical Safety, Environmental Health and Bureau, Ministry of Health and Labour Welfare, . Report on the Deliberation Results: Keytruda (pembrolizumab). https://www.pmda.go.jp/files/000231921.pdfMarch 8–2025

20 

Hellmann MD, Nathanson T, Rizvi H, Creelan BC, Sanchez-Vega F, Ahuja A, Ni A, Novik JB, Mangarin LMB, Abu-Akeel M, et al: Genomic features of response to combination immunotherapy in patients with advanced non-small-cell lung cancer. Cancer Cell. 33:843–852.e4. 2018. View Article : Google Scholar : PubMed/NCBI

21 

Vanderwalde A, Spetzler D, Xiao N, Gatalica Z and Marshall J: Microsatellite instability status determined by next-generation sequencing and compared with PD-L1 and tumor mutational burden in 11,348 patients. Cancer Med. 7:746–756. 2018. View Article : Google Scholar : PubMed/NCBI

22 

Umar A, Boland CR, Terdiman JP, Syngal S, de la Chapelle A, Rüschoff J, Fishel R, Lindor NM, Burgart LJ, Hamelin R, et al: Revised Bethesda Guidelines for hereditary nonpolyposis colorectal cancer (Lynch syndrome) and microsatellite instability. J Natl Cancer Inst. 96:261–268. 2004. View Article : Google Scholar : PubMed/NCBI

23 

Vasen HF, Watson P, Mecklin JP and Lynch HT: New clinical criteria for hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome) proposed by the international collaborative group on HNPCC. Gastroenterology. 116:1453–1456. 1999. View Article : Google Scholar : PubMed/NCBI

24 

Kaneko T, Sekine A, Komatsu S, Otoshi R, Haga S, Tagami Y, Kaneko T and Ogura T: Successful pembrolizumab treatment for microsatellite instability-high thymoma: A case report. Respir Investig. 62:517–519. 2024. View Article : Google Scholar : PubMed/NCBI

25 

de Camargo Correia GC, Tawfiq R, Lou Y, Zhao Y, Li S, Ernani V, Parikh K and Manochakian R: Immune checkpoint inhibitors (ICI) in thymic epithelial tumors (TET): A real world assessment of efficacy and toxicity. J Clin Oncol. 43 (Suppl 16):e201412025.

Related Articles

  • Abstract
  • View
  • Download
  • Twitter
Copy and paste a formatted citation
Spandidos Publications style
Nakagawa T, Aruga N, Watanabe H, Masuda R, Yamada S and Iwazaki M: <p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>. Oncol Lett 31: 121, 2026.
APA
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., & Iwazaki, M. (2026). <p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>. Oncology Letters, 31, 121. https://doi.org/10.3892/ol.2026.15474
MLA
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., Iwazaki, M."<p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>". Oncology Letters 31.4 (2026): 121.
Chicago
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., Iwazaki, M."<p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>". Oncology Letters 31, no. 4 (2026): 121. https://doi.org/10.3892/ol.2026.15474
Copy and paste a formatted citation
x
Spandidos Publications style
Nakagawa T, Aruga N, Watanabe H, Masuda R, Yamada S and Iwazaki M: <p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>. Oncol Lett 31: 121, 2026.
APA
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., & Iwazaki, M. (2026). <p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>. Oncology Letters, 31, 121. https://doi.org/10.3892/ol.2026.15474
MLA
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., Iwazaki, M."<p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>". Oncology Letters 31.4 (2026): 121.
Chicago
Nakagawa, T., Aruga, N., Watanabe, H., Masuda, R., Yamada, S., Iwazaki, M."<p>Recurrent microsatellite instability‑high thymic carcinoma showing complete response to immune checkpoint inhibitor: A case report</p>". Oncology Letters 31, no. 4 (2026): 121. https://doi.org/10.3892/ol.2026.15474
Follow us
  • Twitter
  • LinkedIn
  • Facebook
About
  • Spandidos Publications
  • Careers
  • Cookie Policy
  • Privacy Policy
How can we help?
  • Help
  • Live Chat
  • Contact
  • Email to our Support Team