Introduction: Although undifferentiated pleomorphic sarcomas are aggressive, a subset of these tumors are immunogenic and may respond to immunotherapy.
Case presentation: A 69-year-old man developed bilateral adrenal tumors and underwent bilateral adrenalectomy. Pathological examination revealed undifferentiated pleomorphic sarcoma harboring tertiary lymphoid structures and infiltration of CD8+ T cells. Genome profiling revealed PD-L1 amplification, microsatellite instability, and a high tumor mutation burden. He developed local recurrence and multiple peritoneal dissemination 2 months after surgery; adriamycin chemotherapy was ineffective for these lesions. Sustained complete remission of all lesions was achieved by administering pembrolizumab.
Conclusion: Immunohistochemical analysis focusing on tertiary lymphoid structures and genome profiling to evaluate microsatellite instability and tumor mutation burden are essential for precision medicine and informed clinical decision-making when treating advanced undifferentiated pleomorphic sarcoma.
Keywords: immunotherapy; tertiary lymphoid structures; undifferentiated pleomorphic sarcomas.
© 2023 The Authors. IJU Case Reports published by John Wiley & Sons Australia, Ltd on behalf of Japanese Urological Association.