Non-Invasive Papillary Urothelial Neoplasms of the Bladder: A Study of Tumors with Borderline Features
Jennifer M Oliver-Krasinski, Jean Hou, Lara R Harik. Columbia University - New York Presbyterian Hospital, New York, NY
Background: The 2004 WHO/ISUP system is currently used for grading non-invasive papillary urothelial neoplasms of the bladder (PUNB) and classifies them into papilloma, papillary urothelial neoplasms of low malignant potential (PUNLMP), papillary urothelial carcinoma low grade (LG) and high grade (HG). Although most tumors can be classified into these categories with ease, some tumors show borderline features and are subject to interobserver variability, which is problematic in the setting of LG versus HG, a distinction that changes subsequent patient therapy.
Design: 99 cases of PUNB are identified between 1990 and 2010. Only patients with initial presentations of non-invasive PUNB are included. Patients with less than 2 year follow up (F/U) are excluded unless they have developed recurrence or progression. Tumors are classified as borderline tumors if they are either 1) Predominantly LG with focal HG (< 50% HG), 2) Architecturally and cytologically LG but have areas of mitoses >5/10HPF, or 3) Show marked nuclear pleomorphism but are architecturally LG, with low mitotic count and absence of necrosis or presence of focal punctate necrosis. Recurrence is defined as occurring after 3 months of F/U. Progression is defined as progression in grade, or stage (invasion or metastases).
Results: The average age is 68y (35-86y); M:F: 2.8:1; F/U: 68.7 mo (5.7-243 mo), median=56 mo. The cases are classified as PUNLMP (n=5), LG (n=33), borderline tumors (LG/HG) (n=39) and HG (n=22) (table 1). Within the borderline tumors, category 1 tumors show similar rates of recurrence and progression as LG. Category 2 tumors show a high rate of recurrence and grade progression, however none progressed by stage. Category 3 tumors show similar rates of recurrence and grade progression as LG; however, the rate of stage progression is intermediate between LG and HG.
|Cases||Recurrence N (%)||Grade Progression N (%)||Stage Progression N (%)|
|LG||33||23 (70)||5 (15)||2 (6)|
|Borderline total||39||28 (72)||5 (13)||4 (10)|
|LG/HG mix, <50% HG (1)||15||10 (67)||0 (0)||1 (6)|
|LG, increased mitoses (2)||9||9 (100)||3 (33)||0 (0)|
|LG, increased nuclear atypia (3)||15||9 (60)||2 (13)||3 (20)|
|HG||22||17 (77)||-||7 (32)|