Urine Cytology Findings in Cases of Pseudocarcinomatous Urothelial Hyperplasia of the Bladder Often Represent a Diagnostic Challenge

CONTEXT.—

Pseudocarcinomatous urothelial hyperplasia (PCUH) architecturally and cytologically mimics cancer. The urine cytology features of PCUH have not been described.

OBJECTIVE.—

To describe PCUH features in urine cytology.

DESIGN.—

We reviewed urine cytology cases with concurrent PCUH tissue specimens from 5 academic institutions and classified them by using The Paris System criteria.

RESULTS.—

Thirty-nine patients included 31 men and 8 women with a mean age of 67 years (range, 39-87 years). All patients had prior pelvic irradiation, and most presented with hematuria (n = 27). The specimens included voided urine (n = 16); bladder washing (n = 11); and urine, not otherwise specified (n = 12). The specimen preparation included cytospin (n = 29) and ThinPrep (n = 10). Original interpretations were negative for high-grade urothelial carcinoma (n = 28), atypical urothelial cells (AUCs; n = 10), and high-grade urothelial carcinoma (HGUC; n = 1). Twenty-five urine specimens (64%) had findings of PCUH. These specimens were moderately cellular and composed of sheets, cohesive groups, or isolated urothelial cells. Nucleoli were present in 23 cases. The nuclear membrane was smooth to irregular (n = 9), smooth (n = 8), and irregular (n = 8). The chromatin was glassy (n = 8), vesicular (n = 7), hyperchromatic (n = 7), and vesicular to finely granular (n = 3). The cytoplasm varied from dense squamoid, to finely vacuolated, to vacuolated. Nucleomegaly was observed in all 25 specimens, and nuclear-cytoplasmic ratio greater than 0.5 was seen in 11 of 25 cases (44%). The background contained acute inflammation (n = 14), was clean (n = 9), and contained red blood cells (n = 2). All cases originally interpreted as AUCs and HGUC had PCUH features.

CONCLUSIONS.—

PCUH urine features can overlap with AUCs, HGUC, and other nonurothelial malignancies. In our cohort, 44% (11 of 25) of urine specimens with PCUH changes were initially misclassified. Recognition of cytologic features of PCUH is important to avoid overcalling reactive changes.

Tumour-like lesions of the urinary bladder

There are a number of benign epithelial proliferations in the bladder that may be difficult to distinguish from carcinomas, including urothelial carcinoma and its variants, squamous cell carcinoma and adenocarcinoma. If misdiagnosed, there is the potential for over treatment, with its attendant risk of complications, as well as errors relating to prognostic assessment. In the case of the misdiagnosis of high grade proliferative lesions that mimic invasive carcinoma, unnecessary radical surgery, chemotherapy and radiotherapy may result. Similarly, the misdiagnosis of lesions that have the appearance of low grade carcinoma can prompt a lifetime of radiological investigation and cystoscopies. In this review, we discuss a variety of entities that may be diagnostically challenging and emphasise the importance of identifying key morphological features that have diagnostic utility. We also highlight the importance of relevant clinical information and the clinical settings in which these lesions may occur. In this review we have divided the lesions on the basis of morphology in order to facilitate discussion relating to the differential diagnosis. The architectural patterns we discuss include papillary lesions (polypoid/papillary cystitis and papillary urothelial hyperplasia), pseudocarcinomatous proliferations (pseudocarcinomatous urothelial hyperplasia, florid proliferation of von Brunn nests and fibroepithelial polyps), glandular lesions (intestinal metaplasia and müllerianosis) and lesions with several different patterns (prostatic type urethral polyps and nephrogenic adenoma or metaplasia).

Iatrogenic Disease of the Genitourinary Tract

Iatrogenic disease is defined as illness caused by diagnostic procedures or treatment given by health care professionals. More recently described treatment complications involving the genitourinary tract include newly recognized variants of renal carcinoma in the setting of dialysis/end-stage renal disease, treatment effect in genitourinary carcinomas, and medical renal disease caused by drug therapies, including immunotherapy. The objective of this review is to cover iatrogenic inflammatory diseases, pseudotumors and tumors of the kidney, bladder, prostate, testis and paratestis of most interest to surgical pathologists. For this reason, disease caused by the following will not be covered: iatrogenic glomerulonephritis, self-inflicted injury including the introduction of foreign bodies, surgical error, drugs of abuse and herbal medications, and iatrogenic disease in the transplant setting including ischemia/reperfusion injury. Emphasis is placed upon commonly encountered diseases in order to ensure that the review is of utility to practicing pathologists. The clinical context, pathophysiology and histopathology of each disease entity are covered.