[462] Urine Cytomorphology of Micropapillary Urothelial Carcinoma.

Bing Zhu, Ritu Nayar, Ximing Yang, Stephen M Rohan, Xiaoqi Lin. Northwestern University, Chicago, IL

Background: Micropapillary urothelial carcinoma (MPUC) is a rare variant of UC with an aggressive clinical course in terms of higher T stage, higher incidence of lymphovascular invasion, and higher incidence of lymph node and/or distant metastasis (our data not shown here). However, cytologic features of MPUC in urine cytology have not been well described. The aims of this study were to describe cytologic features of MPUC and compare them with those of high grade UC (HGUC).
Design: 21 urinary specimens (11 voided and 10 washings) from 14 patients with diagnosis of MPUC on follow-up surgical specimens, and 28 specimens (14 voided and 14 washings) from 28 patients with HGUC were retrieved. The cytologic features, single cell patter, papillary architecture, flat sheets/nests, 3 dimensional clusters, micropapillary (inside-out, acinar-like), nuclear grade, cytoplasm quantity, cytoplasmic vacuoles, and necrosis, were revaluated. Clinical follow-up was also reviewed.
Results:

Table 1. Cytologic features of MP-UC and HG-UC.

	Single Cells	Papillary architecture	Flat Sheets	3-Dimensional Clusters	Micropapillary	Nuclear Grade	Cytoplasmic vacuoles
MP-UC	100%	47.6%	38.1%	85.7%	81.0%	2.7 ± 0.6	47.1%
HG-UC	100%	35.7%	35.7%	85.7%	14.3%	2.3 ± 0.7	14.3%
P Value	1.000	0.099	0.181	0.186	< 0.001	0.026	< 0.01

Chi Square test.

Table 2. Re-evaluation of urine specimens.

	MP-UC			HG-UC
	Original	Re-evaluation	Possible MP	Original	Re-evaluation	Possible MP
UC	17/21 (81%)	20/21 (95%)	17/21 (81%)	13/28 (46%)	22/28 (79%)	4/28 (14%)
Suspicious for UC	1/21 (5%)		P < 0.001	2/28 (7%)	3/28 (11%)
Atypical UC	1/21 (5%)	1/21 (5%)		6/28 (21%)	3/28 (11%)
Negative	2/21 (10%)			7/28 (25%)

Chi Square test.

8/14 (57%) MPUC and 1/28 (4%) HGUC showed metastasis to lymph node and/or distant organs (P < 0.001).
Conclusions: 1. On urine cytology, micropapillary architecture and cytoplasmic vacuoles are the two most useful features for the diagnosis of MPUC with sensitivity of 81%, specificity of 82%, positive predictive value of 77% and negative predictive value of 85%.
2. Nuclear grade of MPUC is slightly higher than that of HGUC.
3. MPUC can present with single cells, papillary architecture, flat sheets/nests, 3 dimensional clusters, and necrosis in urine cytology as seen in HGUC.
4. Patients with MPUC show higher incidence of lymph node and distal metastasis than HGUC (57% vs. 4%).
5. Careful evaluation of urine cytology for possible MPUC is very helpful to guide clinicians in choosing deep biopsy for possible MPUC cases, and predicting metastasis and prognosis.
Category: Cytopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 65, Wednesday Afternoon