Micropapillary Urothelial Carcinoma: Cytologic Features in Exfoliative Urinary Specimens.
Jonas Heymann, Andrew T Turk, Anjali Saqi, John P Crapanzano. Columbia University Medical Center, New York, NY
Background: Micropapillary urothelial carcinoma (MUC) is a rare, high grade variant of urothelial carcinoma (UC) that is often invasive into muscle and lymphovascular spaces at presentation and carries a poor prognosis. Extent of micropapillary histology correlates inversely with prognosis. Cystectomy for low stage tumors (pTa, pT1) with micropapillary histology may be appropriate. Recognizing this high grade variant in urinary cytology, the most widely used non-invasive test to detect UC, is important in distinguishing this aggressive tumor from the relatively less aggressive UCs.
Design: A retrospective search for histologically confirmed MUCs with concurrent or near-concurrent urinary cytology was performed. Cases with sarcomatoid differentiation, small cell carcinoma, or mucinous adenocarcinoma were excluded from analysis. All cytologic specimens were prepared using ThinPrep. Cytologic findings, including cell arrangement, nuclear and cytoplasmic features, and N:C were examined.
Results: Twenty-three cases from 22 patients were identified over a 4 year period. Micropapillary clusters and single cells were present in 12 and 23 specimens, respectively. Chromatin was hyperchromatic (n=6), intermediate (n=15), and bland (n=2). Irregular nuclear contours were present in all specimens and nucleoli in 17 specimens. Cytoplasmic vacuoles were evident in 13 cases, including solitary vacuoles (n=6) and multiple vacuoles (n=8); cells in 2 specimens variably demonstrated solitary and multiple vacuolization. All cases demonstrated increased N:C. Corresponding surgical pathology specimens showed varying degrees of micropapillary architecture.
Conclusions: Urinary specimens from patients with histologically confirmed MUC show malignant cells that usually exhibit high grade cytologic features, including marked hyperchromasia, irregular nuclear contours, and clusters with micropapillary architecture. Cytoplasmic vacuoles are also frequently present, a feature not typically seen in UC. These cytologic findings may be useful in managing patients with MUC. Further investigation of urine cytology for diagnostic features distinguishing MUC from other variants is warranted.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 64, Wednesday Afternoon