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The following is a summary of “Pitfalls of frozen section diagnosis in ureter margin evaluation of plasmacytoid urothelial carcinoma of urinary bladder,” published in the November 2024 issue of Urology by Kim et al. 

Plasmacytoid urothelial carcinoma (PUC) is a rare, aggressive subtype with a poor prognosis. It is often presented at advanced stages. 

Researchers conducted a retrospective study comparing PUC with positive ureter resection margin (+ URM) with PUC with negative URMs (-URM). 

They reviewed pathology reports from 2017 to 2023 for cases diagnosed with PUC during radical cystectomy (RC), analyzing H&E slides where the plasmacytoid component exceeded 25%. Frozen section analyses (FSAs) and permanent section analyses (PSAs) of URM were conducted to evaluate the specimens. 

The results showed that 15 patients with a plasmacytoid component >25% were identified. Compared with -URM cases, +URM cases were more commonly located at the trigone or bladder neck, with all +URM cases involving the ureter orifice. Of the 6 PSA-positive cases, 50% showed discrepancies with FSA. About 3 +URM cases exhibited PUC cells in the submucosa or muscularis propria, while the others showed invasion along the adventitia. Discordant cases had consistent adventitia invasion, with sectioning errors and misinterpretation as primary causes. 

Investigators demonstrated 2 patterns of tumor infiltration along the ureter and emphasized the importance of comparing FSA with PSA in PUC. They highlighted the need for comprehensive management strategies and further studies to optimize care for patients with PUC. 

Source: bmcurol.biomedcentral.com/articles/10.1186/s12894-024-01643-0