Urothelial Carcinoma of the Upper Urinary Tract A patient presented with gross hematuria and underwent radical nephroureterectomy. Grossly, the kidney was remarkable for an extensive papillary neoplasm involving the renal pelvis and calyces without obvious extension into the renal parenchyma (fig. 1). Histologically, the neoplasm was a noninvasive low grade papillary urothelial carcinoma characterized by thickened neoplastic urothelium lining fibrovascular cores (fig. 2). Architecturally, there was fusion of the papillary fronds with complex branching configurations. Urothelial carcinomas of the upper urinary tract (renal pelvis and ureter) constitute about 5% to 10% of all urothelial carcinomas1e5 and, although they share many similarities with urothelial carcinoma of the bladder, there are also significant differences.3 Macroscopically, upper tract urothelial carcinoma may be solitary or multifocal. Papillary or sessile growth can be observed grossly, and solid, nodular, ulcerated or diffusely infiltrative masses may be found with invasive urothelial carcinomas. Gross evidence of invasion may be detected as
thickening of the ureter and/or renal pelvis as well as formation of solid tumor in the renal parenchyma.1 In our case the tumor was extensive, exhibited exophytic growth into the renal pelvis and calyces, and was papillary without gross evidence of invasion (fig. 1). Some of these tumors can be large, with a mean size of 3.7 cm, ranging up to 9 cm.2 Microscopically, most upper tract urothelial carcinomas are high grade,2,5 unlike bladder carcinomas. In our case the urothelial carcinoma was low grade, which was assigned to 29% of renal pelvic urothelial carcinomas in 1 series.2 Despite tumor size, no invasion was detected. A substantial percentage of patients (45%) with upper tract urothelial carcinoma have locally advanced disease (pT2 or higher) at nephroureterectomy.2 The most significant prognostic factor for patients with upper tract urothelial carcinoma is TNM stage.2,6 Additional pathological features that may be independent predictors of clinical outcome after radical nephroureterectomy are extensive tumor
Figure 1. Papillary urothelial carcinoma of renal pelvicalyceal system.
Figure 2. Low grade papillary urothelial carcinoma with thickened neoplastic urothelium and central fibrovascular core.
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necrosis, sessile tumor architecture and lymphovascular invasion.6
3. Green DA, Rink M, Xylinas E et al: Urothelial carcinoma of the bladder and upper tract: disparate twins. J Urol 2013; 189: 1214.
Peter A. Humphrey
4. Gupta R, Paner GP and Amin MB: Neoplasms of the upper urinary tract: a review with focus on urothelial carcinoma of the pelvicalyceal system and aspects related to its diagnosis and reporting. Adv Anat Pathol 2008; 15: 127.
Department of Pathology Yale University School of Medicine New Haven, Connecticut 1. Delahunt B and Samaratunga H: Pathology of the renal pelvis and ureter. In: Urological Pathology. Edited by MB Amin, DJ Grignon, JR Srigley et al. Philadelphia: Wolters Kluwer/Lippincott Williams and Wilkins 2014; pp 261e294. 2. Olgac S, Mazumdar M, Dalbagni G et al: Urothelial carcinoma of the renal pelvis: a clinicopathologic study of 130 cases. Am J Surg Pathol 2004; 28: 1545.
5. Perez-Montiel D, Wakely PE Jr, Hes O et al: High-grade urothelial carcinoma of the renal pelvis: clinicopathologic study of 108 cases with emphasis on unusual morphologic variants. Mod Pathol 2006; 19: 494. 6. Chromecki TF, Bensalah K, Remzi M et al: Prognostic factors for upper urinary tract urothelial carcinoma. Nat Rev Urol 2011; 8: 440.