CASE REPORT article
Front. Oncol.
Sec. Cancer Immunity and Immunotherapy
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1552411
This article is part of the Research TopicAdvancements in Solid Tumor Immunotherapy: Enhancing Efficacy and Overcoming ResistanceView all articles
MS-stable/TMB-high Pleomorphic Liposarcoma Successfully Treated with Pembrolizumab: A Case Report
Provisionally accepted
Satoshi Miwa1,2
Hiroshi Kobayashi2*Toshihide Hirai1,2Koichi Okajima2Yuki Ishibashi2Yusuke Tsuda2Liuzhe Zhang2Toshihiko Ando2Aya Shinozaki-Ushiku3
Sakae Tanaka2- 1Department of Musculoskeletal Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan
- 2Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
- 3Department of Pathology, The University of Tokyo Hospital, Tokyo, Japan
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Pleomorphic liposarcoma (PLPS) is a rare and aggressive subtype of liposarcoma with limited treatment options. Despite studies on immune checkpoint inhibitors (ICIs) in sarcomas, there have been few reports involving PLPS. Furthermore, the significance of tumor mutation burden (TMB)-high, a known biomarker for ICIs in various solid tumors, remains unclear in sarcomas. Herein, we report the case of a 41-year-old man with postoperative liver metastasis of microsatellite (MS)-stable/TMB-high PLPS who achieved successful remission with pembrolizumab, an anti-programmed cell death protein 1 inhibitor. Initially, the patient underwent extensive resection for primary PLPS in the distal left thigh. The diagnosis of lung metastases 3 months after prompted five courses of doxorubicin and ifosfamide, resulting in stable disease. Subsequent thoracoscopic pulmonary metastasectomy allowed surgical removal of the lung metastases. However, multiple liver metastases developed 9 months following the primary extensive resection. Cancer genome profiling revealed a mutation in MSH6, MS-stable status, and a high TMB of 14.5/Mb. Pembrolizumab was initiated for a total of 35 courses at 10 months postoperatively, significantly reducing liver metastases. These findings suggest the potential of TMB-high as a predictor of ICI response in sarcomas.
Keywords: Pleomorphic liposarcoma, Tumor mutation burden (TMB), Immune checkpoint inhibitors (ICIs), Pembrolizumab, liver metastasis
Received: 28 Dec 2024; Accepted: 15 May 2025.
Copyright: © 2025 Miwa, Kobayashi, Hirai, Okajima, Ishibashi, Tsuda, Zhang, Ando, Shinozaki-Ushiku and Tanaka. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Hiroshi Kobayashi, Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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