Testicular Hypoplasia
Cause: Testicular hypoplasia is a rare condition depicted by complete absence or severe reduction of spermatic tissue in one or both testes. The cause of this condition is unknown, however, it is suspected that this may occur as a developmental disorder in which the germinal cells fail to migrate to the fetal testes. An alternative explanation is that the germinal cells are destroyed during fetal development.
Symptoms: Testicular hypoplasia is suspected in young dogs in which one or both testes appear unusually small.
Diagnosis: Diminished size can be confirmed by ultrasound imaging. Biopsy of the testes indicates a decrease or absence of the seminiferous tubules and spermatogonia, which comprise about 50-70% of testicular size. Because testes of dogs with testicular hypoplasia usually have Leydig cells, testosterone is still produced and sexual drive (libido) is typically normal in these males.
Prognosis and Treatment: Dogs with bilateral testicular hypoplasia are sterile. Treatment with gonadotropins to stimulate the proliferation of germinal cells has thus far proven ineffective for treatment of this disorder.
Testicular Degeneration
Cause: Inflammatory and non-inflammatory conditions can result in loss of seminiferous tubules, germinal cells, interstitial cells, and spermatogonia within the testes. In addition to traumatic conditions like inguinoscrotal hernia, testicular degeneration also occurs commonly in middle-aged dogs as an idiopathic condition.
Symptoms: In early stages, testicular degeneration may not be apparent by testicular appearance. As the condition progresses, the testes eventually become small and soft. Libido is typically normal because the testosterone-producing Leydig cells are not involved in the degenerative process.
Diagnosis: Testicular degeneration is confirmed by testicular biopsy.
Treatment and Prognosis: Treatment of testicular degeneration is dependent upon identification and prompt treatment of the underlying inflammatory or non-inflammatory condition. Idiopathic testicular degeneration that occurs in middle-aged dogs is unresponsive to treatment and thus prognosis for fertility is considered poor.
Cause: Testicular hypoplasia is a rare condition depicted by complete absence or severe reduction of spermatic tissue in one or both testes. The cause of this condition is unknown, however, it is suspected that this may occur as a developmental disorder in which the germinal cells fail to migrate to the fetal testes. An alternative explanation is that the germinal cells are destroyed during fetal development.
Symptoms: Testicular hypoplasia is suspected in young dogs in which one or both testes appear unusually small.
Diagnosis: Diminished size can be confirmed by ultrasound imaging. Biopsy of the testes indicates a decrease or absence of the seminiferous tubules and spermatogonia, which comprise about 50-70% of testicular size. Because testes of dogs with testicular hypoplasia usually have Leydig cells, testosterone is still produced and sexual drive (libido) is typically normal in these males.
Prognosis and Treatment: Dogs with bilateral testicular hypoplasia are sterile. Treatment with gonadotropins to stimulate the proliferation of germinal cells has thus far proven ineffective for treatment of this disorder.
Testicular Degeneration
Cause: Inflammatory and non-inflammatory conditions can result in loss of seminiferous tubules, germinal cells, interstitial cells, and spermatogonia within the testes. In addition to traumatic conditions like inguinoscrotal hernia, testicular degeneration also occurs commonly in middle-aged dogs as an idiopathic condition.
Symptoms: In early stages, testicular degeneration may not be apparent by testicular appearance. As the condition progresses, the testes eventually become small and soft. Libido is typically normal because the testosterone-producing Leydig cells are not involved in the degenerative process.
Diagnosis: Testicular degeneration is confirmed by testicular biopsy.
Treatment and Prognosis: Treatment of testicular degeneration is dependent upon identification and prompt treatment of the underlying inflammatory or non-inflammatory condition. Idiopathic testicular degeneration that occurs in middle-aged dogs is unresponsive to treatment and thus prognosis for fertility is considered poor.