Response to immunotherapy in a patient with advanced epithelioid sarcoma of adrenal gland: A case report.

Epithelioid sarcoma (ES) is a rare and highly invasive soft tissue malignant tumor with uncertain histogenesis. The localization of ES in the adrenal gland is rather unusual. The present study reported a case of stage IV ES in the adrenal gland of a 28-year-old male. The tissue biopsy of adrenal and lung lesions revealed epithelioid cells. Immunohistochemistry indicated that the tumor cells were strongly positive for cytokeratin (CK)8, CK, epithelial membrane antigen (EMA), CD34 and programmed cell death protein 1 ligand (PD-L1) but negative for nuclear integrase interactor 1 expression. The next-generation sequencing technology was applied using peripheral blood, indicating a low tumor mutation burden of 4.11 mutations (Muts)/Mb and somatic mutations in SMARCB1. After diagnosis, the patient underwent unsuccessful palliative chemotherapy and radiotherapy. However, application of immune checkpoint inhibitors (ICIs) achieved partial remission and the overall survival reached 25 months. ICI monotherapy may be a feasible treatment for patients with ES with a strong expression of PD-L1.