ABSTRACT

Background: Urothelial carcinoma of the urinary bladder represents 90% of all primary tumors of this organ . The depth of the invasion particularly for the muscularispropria is the most important prognostic and therapeutic determinator . Therefore, differentiation between muscularispropria and muscularis mucosa is essential for the proper treatment and avoiding over staging or under staging.

Aim: To evaluate the role of smoothelin and vimentin expression in differentiation between muscularis mucosa and muscularisproperia for better assessment of invasion level and give correct staging.

Method: This study was carried out on 60 specimens of primary urothelial carcinoma .

Results: In the sixty examined specimen , muscularispropria positivity for smoothelin was found in all 60 cases, while vimentin positivity for muscularis mucosa was found in 50 cases .Three of the cases which were staged as Ta at the H&E staining were upstaged to T1 after staining with vimentin; while five of the cases which were staged as T1 at the H&E staining were upstaged to T2 after staining with smoothelin . Therefore; smoothelin and vimentin can be used in differentiation between muscularis mucosa and muscularisproperia for better assessment of invasion level and give correct staging.

Conclusions: differentiation of muscularis mucosa from muscularispropria can be made histologically by using smoothelin and vimentinimmunostaining.

Keywords: Muscularis mucosa, Vimentin, Muscularispropria , Smoothelin, Urothelial CA urinary bladder.