Abstract
Upper tract urothelial carcinoma (UTUC) is uncommon and aggressive, and evidence for perioperative antibody-drug conjugate or immunotherapy remains limited. We report a 59-year-old man with biomarker-non-enriched high-risk ureteral UTUC treated with four cycles of toripalimab plus disitamab vedotin before planned surgery. Magnetic resonance urography, urine cytology, and ureteroscopic biopsy supported high-grade UTUC with glandular differentiation; CDX-2, villin, and β-catenin positivity prompted exclusion of a gastrointestinal primary. The biopsy showed HER2 0, TROP2 0, and low PD-L1 expression. Restaging MRI and endoscopy demonstrated reduced visible lesion extent; axial dimensions decreased from 3.68 × 2.69 cm to 2.14 × 1.55 cm. No formal RECIST 1.1 category was assigned because imaging was not standardized. The patient then underwent planned laparoscopic radical nephroureterectomy with bladder cuff excision. Final pathology showed poorly differentiated ureteral urothelial carcinoma with marked histological heterogeneity, staged ypT2Nx. Recovery was uneventful. At the latest follow-up on May 28, 2026, the patient remained well, and surveillance cystoscopy showed no evident intravesical abnormality. This case highlights the limited representativeness of pretreatment biopsy in UTUC. The observed lesion reduction is hypothesis-generating and should not be interpreted as evidence of clinical efficacy. Standardized response assessment and longer follow-up are required.