腎盂尿路上皮癌伴隨鈣化偽裝成腎結石：一個診斷困難的病例報告

郭炫廷、張心湜、王曉暹、陳光國、謝啟誠、蔡昇翰、楊景偉 與 黃家倫

振興醫療財團法人振興醫院泌尿部

Renal Pelvis Urothelial Carcinoma with Calcification Masquerading as Nephrolithiasis: A Case Report of Diagnostic Dilemma

Hsuan-Ting Kuo, Luke S. Chang, Hsiao-Hsien Wang, Kuang-Kuo Chen, Chi-Chen Hsieh, Sheng-Han Tsai, Ching-Wei Yang and Chia-Lun Hwang

Department of Urology, Cheng Hsin General Hospital, Taipei, Taiwan

Introduction: Urothelial carcinoma constitutes up to 90% of renal pelvis malignancies. Calcifications within such tumors are rare, manifesting in merely 2-7% of cases, and may be misinterpreted as urolithiasis. We report a unique presentation of right renal pelvis urothelial carcinoma with concomitant calcification, initially mistaken for renal calculi.

Presentation of case: A 57-year-old female with no significant medical history presented to the emergency department complaining of right flank pain and gross hematuria. She was afebrile, with right costovertebral angle tenderness on physical examination. Laboratory tests showed leukocytosis with a left shift (WBC=10500/μL, seg=83.5%) and urinalysis showed hematuria (RBC ≥ 100/HPF) and proteinuria (1+). A KUB film did not indicate the presence of stones. Non-contrast abdominal CT imaging revealed right hydronephrosis with punctate calcification in the renal pelvis, suggestive of renal stones, and a right ureterovesical junction (UVJ) stone according to the radiological report. The patient underwent right ureterorenoscopy (URS) lithotripsy, where operative findings included small stone fragments at the UVJ associated with a regional stricture and mucosal swelling. At the renal pelvis level, the semi-rigid ureteroscopy uncovered papillary tumors with surface calcifications, potentially the origin of the UVJ stone. The URS biopsy confirmed low-grade, non-invasive papillary urothelial carcinoma.

Discussion: Various etiologies may contribute to calcification in urothelial carcinoma, including tumor necrosis, hemorrhage, cystic degeneration, local ischemia, infection, and alkaline urine potentiating calcium phosphate deposition. Distinguishing tumor-related calcifications from other calcific renal pathologies, such as nephrolithiasis or renal tuberculosis, is challenging on non-contrast CT scans. While calcified renal cell carcinoma being misdiagnosed as nephrolithiasis is documented, our case represents a novel report of urothelial carcinoma with downstream calcification leading to hydroureteronephrosis. Clinicians should maintain a high index of suspicion for alternate pathologies when encountering atypical calcification patterns in the renal pelvis.