Diagnostic value of cytology of voided urine.

There are 961 new cases and approximately 366 deaths from urothelial carcinoma registered annually in Croatia. Exfoliative urinary cytology has important role in detection of high grade urinary tumors, invasive and in situ lesions respectively. In contrast to cystoscopy and biopsy, cytology is a noninvasive method which is easily repeated. The aim of this retrospective study was to assess value of urinary cytology in our institution. For this purpose only patients with histological diagnosis and clinical follow up were considered. There were 138 urine specimens with cytological diagnosis of dyskaryosis, suspicious for malignancy or malignant and histology and follow up data examined at our Department of Clinical Cytology between 2004 and 2011. Cytological diagnosis suspicious for malignancy and malignant were considered positive and the results were correlated with histological diagnosis according to the WHO histological classification of tumors of the urinary tract. Patients with negative histological findings were followed for the next two years. The positive predictive value of cytological detection of malignant urothelial lesions was 91.8%. In 10 cases cytological diagnosis of malignancy was not confirmed histologically or clinically which makes the total of 8.2% of false positive reports. Of the total of detected malignant urothelial lesions 90.9% are high grade lesions and only 9.1% low-grade lesions; 67.3% are invasive lesions and 32.7% non-invasive lesions. Cytological findings of dyskariotyc cells requires further urological investigation because such findings in further processing prove the presence of tumor in 93.8% of cases. In conclusion: cytology is very good diagnostic tool for detection of high grade invasive and noninvasive carcinomas of the urinary tract. In order to make it more efficient we need to study its limits carefully, define diagnostic criteria and reach consensus in nomenclature.