Objective: Prostate cancers are usually seen in men over 60 years of age. The incidence under the age of 40 is very rare and they are the most common malignant tumors in men. After lung cancer, it is the second most common cause of death associated to cancer in men . The most common histopathological type is adenocarcinoma. The definitive diagnosis is made by histopathological examination. Rectal touch, radiological imaging, and prostate-specific antigen (PSA) in blood test are helpful in diagnosis. transurethral resection of the prostate (TURP) is a surgical procedure for patients with a PSA value of less than 4 ng / mL and prediagnosis of benign prostatic hyperplasia (BPH). The aim of the study is to share the incidences of incidental prostate cancer in our TURP materials with the guidance of literature, to contribute to the diagnosis, treatment, and follow-up of the patients.

Materials and Methods: A retrospective analysis on 1033 TURP materials obtained between 2013-2018 at our university hospital was performed. Cases with a prostate-specific antigen (PSA) level of less than 4 ng/ml and with a preliminary diagnosis of benign prostatic hyperplasia (BPH) were included in the study. The sections taken from paraffin blocks of the cases were examined with Hematoxylin-Eosin staining. Due to the loss of the basal layer in the adenocarcinoma of the prostate, cases with atypical small acinar structures were reevaluated with P63 and high molecular weight cytokeratin (HMWCK) immunohistochemical study showing the basal layer.

Results: Histopathological examination revealed an incidental prostatic adenocarcinoma in 13 (1.25%) of 1033 patients without clinical suspicion of malignancy. There was 1%-20% tumor tissue in cases with cancer. In these cases, an average of 8% tumor tissue was observed.

Conclusion: For correct diagnosis of tumor and the calculation of the tumor volume in prostate cancer, all TURP materials should be examined. In the presence of small acinar structures with suspicion of cancer, evaluation with immunohistochemical markers will contribute to decreasing the error rate in the diagnosis.