Toripalimab-based chemoimmunotherapy for unresectable sinonasal NUT carcinoma of the maxillary sinus: a case report

Background Nuclear protein in testis (NUT) carcinoma is an extremely rare and highly aggressive epithelial malignancy driven by NUTM1 rearrangements. Sinonasal involvement is uncommon and often presents with non-specific clinical and radiologic features, leading to delayed diagnosis. Optimal management remains undefined, and outcomes are poor when complete resection is not feasible. Case presentation A 31-year-old man developed progressive numbness and swelling of the left cheek after tooth extraction. Imaging revealed a soft-tissue mass involving the left maxillary sinus with adjacent maxillofacial soft-tissue extension. Endoscopic biopsy demonstrated a poorly differentiated carcinoma with diffuse punctate nuclear NUT expression, high proliferative index (Ki-67 ~50%), and PD-L1 expression in both tumor cells and immune cells. ^18F-FDG PET-CT showed no regional or distant metastases. Given unresectability, the patient received toripalimab (240 mg) combined with docetaxel and cisplatin every 3 weeks. MRI after three cycles showed early radiologic improvement, and further tumor regression was observed after six cycles, consistent with a partial response. The patient subsequently continued on toripalimab-based maintenance therapy with ongoing stable residual disease at the latest follow-up (approximately 5 months after therapy initiation and 6 months from diagnosis). Conclusion To our knowledge, this is the first reported case of toripalimab-based chemoimmunotherapy demonstrating an early partial response and short-term disease control in unresectable maxillary sinus NUT carcinoma. It supports the potential role of PD-1 blockade integrated with platinum–taxane chemotherapy as a component of multimodal management for sinonasal NUT carcinomas.