Histological evaluation of the testicular nubbin in the vanishing testis syndrome

Purpose: We reviewed histopathological studies of the testicular nubbins associated with the vanishing testis syndrome, and determined whether surgical removal is indicated based on the histological findings. Materials and Methods: Between 1983 and 1997 a unilateral testicular nubbin consistent with a vanishing testis was excised in 29 patients an average of 28.6 months old. We retrospectively reviewed the gross pathology reports and microscopic slides, and prospectively performed histochemical stain analysis. Results: Gross evaluation of the specimens revealed an identifiable cord structure in the majority of cases with the vas deferens most commonly identified in 72.4%. No recognizable testicular elements were present in any nubbin. In 3 cases the original pathology report identified cells with features consistent with Leydig cells, which immunohistochemical staining revealed to be atrophied cremasteric muscle fibers. Conclusions: In this series testicular nubbins in vanishing testes contained no viable testicular tissue. Since the risk of testicular cancer in an undescended testis is 8 to 10% and the incidence of viable testicular tissue in these nubbins ranges from 0% in our series to 11% in others, there is only a 0 to 1.1% risk of testicular cancer in the nubbin. Thus, surgical removal may not be warranted.