[1082] Micropapillary Urothelial Carcinoma: A Clinicopathological Study of the Experience of One Academic Center

Bing Zhu, Xiaoqi Lin, Stephen Rohan, Minghao Zhong, Rajen Goyal, Elizabeth Gersbach, Ximing Yang. Northwestern University, Chicago

Background: Micropapillary variant of urothelial carcinoma (MPUC) is a rare UC variant. MPUC have been reported in the urinary bladder, ureter and renal pelvis. Its prognosis and treatment is controversial in the literature. Some studies showed the overall prognosis for MPUC is poor and suggest the early treatment with cystectomy. Whereas one study demonstrated that there is no considerable difference between micropapillary pattern positive and negative groups according to the progression rates in non-muscle-invasive and muscle-invasive groups. In this study, we tried to study the clinicopathological correlation of MPUC, particularly comparison to conventional urothelial carcinoma with same grades and same stages.
Design: 23 MPUC, 135 low grade (LG) and 92 high grade (HG) UC are retrieved. The tumor stage, lymphatic invasion and metastasis including lymph node and distant organs are evaluated. Clinical follow-up is up to 8 years.
Results: See tables.

Table 1. The tumor stage of UC

	Non-invasive	Stage T1	Stage T2	Stage ≥ T3	Median
MPUC (n=23)	1 (4%)	6 (26%)	8 (35%)	8 (35%)	T2/≥ T3
HGUC (n=89)	21 (23%)	25 (27%)	27 (29%)	16 (17%)	T2
LGUC (n=135)	132 (98%)	3 (2%)	0 (0%)	0 (0%)	Non-invasive
Total (N = 247)	155 (62%)	33 (13%)	35 (14%)	24 (10%)	Non-invasive

Table 2. Lymphovascular invasion and distant metastasis of UC

		Lmphovascular Invasion	P Value	Distant Metastasis	P Value
Total	MPUC (n=23)	14 (61%)	< 0.001	12 (52%)	< 0.001
	HGUC (n=89)	8 (9%)		6 (7%)
T1	MPUC (n=6)	2 (33%)	< 0.001	1 (17%)	< 0.001
	HGUC (n=25)	0 (0%)		0 (0%)
T2	MPUC (n=8)	5 (63%)	< 0.001	6 (75%)	< 0.001
	HGUC (n=27)	1 (4%)		3 (11%)
≥ T3	MPUC (n=8)	8 (100%)	0.023	6 (75%)	0.004
	HGUC (n=16)	7 (44%)		3 (19%)

Fisher exact test.


Conclusions: Micropapillary urothelial carcinoma tends to invade deeper (higher stage), and associated with significantly higher incidence of lymphovascular invasion and distant metastasis than conventional high grade urothelial carcinoma, indicating that this variant should be recognized and reported to facilitate studies to understand its molecular mechanism and develop better treatment.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 94, Tuesday Afternoon