Dr.Temesgen, Mulugeta (MD), Assistant professor of pathologyBelachew, Anteneh2021-03-072023-11-052021-03-072023-11-052020-12http://etd.aau.edu.et/handle/123456789/25291Background: Urinary bladder lesions, non-neoplastic and neoplastic, are collectively responsible for significant morbidity and mortality throughout the world. Bladder cancer is the 7th most common cancer worldwide, with an estimated 260,000 new cases occurring each year in men and 76,000 in women. Cancer of the urinary bladder accounts for about 3.2% of all cancers worldwide and is considerably more common in males than in females. According to Globocan, there were 1455 newly diagnosed bladder cancer cases in Ethiopia in 2018 and accounts for 2.2% of cancer death in the same year. According to Addis Ababa Cancer registry, there were a total of 4139 newly diagnosed cancer cases over the period of two years (2012– 2013) and bladder cancer accounts for 5.6% of cases. Objectives: The aim of this study is to determine histopathologic patterns of neoplastic and nonneoplastic bladder lesions in Tikur Anbessa Specialized Hospital. Methods: This was a retrospective cross sectional descriptive study conducted on 625 patients having histopathologic evaluation for bladder lesions at Tikur Anbessa Specialized Hospital from January 01, 2016 to August 30, 2020. Results: From a total of 700 cases reviewed, 625 cases fulfilled the study criteria and included in this study. Out of 625 cases, 597 cases were of TURBT, 27 cases were cystectomy specimens and 1 case was true cut biopsy. The majority of the cases were seen in the age group of 51-60 y(28.5) with a male predominance (76.8%).Hematuria was the most common presenting symptom(59%).non neoplastic lesions accounted for 111 cases (17.8%) ,benign tumors accounted for 16 cases (2.6%) and malignant tumors accounted for 498 cases (79.6%).Urothelial carcinoma (96.4%) were the predominant lesions observed under malignant category, of which low gradenon invasive papillary urothelial carcinoma (51.8%) was the most common subtype. urothelial papilloma was the commonest benign tumor accounting for 7 cases(43.8%).Among nonneoplastic lesions, chronic nonspecific cystitis (20.7%) was the commonest lesion noted. Conclusions: This study demonstrates that majority of the cases were malignant bladder neoplasms of urothelial origin, large number of which was low grade non-invasive papillary urothelial carcinoma.en-USHistopathologic pattern , neoplastic ,non-neoplastic bladderThesis