False-negative biopsy for testicular intraepithelial neoplasia and high-risk features for testicular cancer

The purpose of this report is to emphasize the possibility of false-negativ e biopsies for testicular intraepithelial neoplasia (TIN) in men with high- risk features of testicular cancer and to review the relevant literature. A t the Norwegian Radium Hospital patients in this category are offered the c hance to undergo a testicular biopsy. A patient is described who had a norm al testicular biopsy a decade before presenting with an invasive testicular cancer. Furthermore, this patient is the first case reported with a false- negative biopsy for TIN and a family history of testicular cancer. The eval uation of the biopsies included immunohistochemical staining for c-kit and PlAP (placental-like alkaline phosphatase) in order to diagnose early TIN. Though multifocal or diffuse extension seems to be the most frequent patter n of distribution of TIN, the presented case and another 14 cases from the literature review indicate that the focality of TIN may be a reason for a T IN-negative biopsy.