Incidence of Squamous Metaplasia in Transitional Cell Carcinoma of Urinary Bladder

Squamous metaplasia in transitional cell carcinoma of urinary bladder is considered as an adverse prognostic factor. Those patients have weaker response on therapy and lower survival rate. The aim of our study was to determine the incidence of squamous metaplasia in bioptic material according to histologic grade and growth pattern. In our study we used pathohistological data of 1781 patients operated for urinary bladder cancer in Department of Urology of Sestre milosrdnice University Hospital during the period from 1989 to 2000 Squamous metaplasia was found in 5.7% of patients. According to growth pattern, this phenomenon is more frequent in patients with solid growth pattern. In papillary cancers, the higher incidence of squamous metaplasia was determined in G1 and G2 histologic grade, while in solid growth pattern, the most cases with squamous metaplasia or over 90% were of G3 histologic grade. Muscle layer invasion were present in high percentage of both, papillary and solid urothelial cancers with squamous metaplasia, which imply the high malignant potential of cancers with foci of squamous metaplasia.