Histological evaluation of the testicular nubbin in the vanishing testis syndrome.

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.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.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.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.