上泌尿道尿路上皮癌併發罕見副腫瘤症候群之困難診斷及治療挑戰：

案例報告與文獻回顧

李岳霖、鄒凱亦

衛生福利部雙和醫院 泌尿科

Upper Tract Urothelial Carcinoma Presenting as Rare Paraneoplastic Syndrome:

Diagnostic Pitfalls and Therapeutic Dilemmas, A Case Study and Literature Review

Yueh-Lin Lee, Kai-Yi Tzou

Taipei Medical University Shuang Ho Hospital, Department of Urology, New Taipei City, Taiwan

Introduction: Upper tract urothelial carcinoma (UTUC) accounts for 5-10% of global urothelial carcinomas. However, Taiwan reports a strikingly high rate exceeding 30%, posing a significant oncological challenge. While typically presenting with painless hematuria and flank pain, paraneoplastic manifestations remain rare. We herein report a UTUC case with paraneoplastic syndrome (fever of unknown origin and leukocytosis), highlighting the diagnostic pitfalls and therapeutic dilemmas.

Materials and Methods: A comprehensive PubMed search of UTUC-associated paraneoplastic syndromes was identified through March 2026. After full-text review, relevant articles were analyzed. This case with review is presented alongside to provide insights into clinical treatment considerations.

Case Presentation: A 74-year-old male with herbal medicine use and smoking history presented with gross hematuria for three months. Computed tomography revealed a 3 cm heterogeneous left renal mass. The initial ureteroscopy showed a flat, broad-based ulcerated tumor. Pathology revealed only necrotizing inflammation. However, the clinical course was later complicated by persistent high fever (up to 39°C) and severe leukocytosis (WBC:56.3×10³/μl) with elevated CRP (14mg/dL), both refractory to broad-spectrum antibiotics despite negative cultures. Notably, the patient remained otherwise asymptomatic. After excluding infectious and autoimmune etiologies, a CT-guided biopsy confirmed high-grade invasive urothelial carcinoma with sarcomatoid features. Under the impression of paraneoplastic syndrome (neoplastic fever and leukocytosis), a laparoscopic radical nephroureterectomy with bladder cuff resection(pT3NxM0) was performed. Remarkably, the fever and leukocytosis resolved. However, recurrent fever and leukocytosis occurred one month later. Imaging confirmed rapid lung metastasis. A lung biopsy further revealed non-small cell carcinoma. Under the diagnosis of UTUC with paraneoplastic syndrome and lung metastasis, he received Gemcitabine and Carboplatin per NCCN guidelines now.

Discussion: In our case, two key features provided clinical insights: sarcomatoid histology and paraneoplastic syndrome. The infiltrating, non-papillary nature of sarcomatoid UTUC limited the diagnostic yield of initial ureteroscopy. Furthermore, neoplastic fever and leukocytosis (occurring in <1% of urothelial carcinomas) closely mimicked sepsis, complicating optimal surgical timing.

Conclusion: UTUC presenting with paraneoplastic syndrome is rare and presenting diagnostic and therapeutic difficulties. However, as NCCN guidelines recommended, radical surgery with adjuvant chemotherapy was still the gold standard. Our case underscores the importance of early recognition in managing UTUC with such clinical presentation.