Interstitial cell tumor

From Dog
Histology of extratesticular interstitial cell tumor with the characteristic ‘endocrine’ appearance of interstitial endocrine cells of the testis[1]

Interstitial (Leydig) cell tumor are a testicular disease of dogs.

Testicular tumours in dogs have increased during the past 40 years, suggesting the possible causative role of environmental pollutants[2].

A relationship with retained testicle(s) such as cryptorchidism is present in the dog[3] and extratesticular locations in neutered dogs has been reported, though extremely rare[4].

Interstitial cell tumors are the most common testicular tumor in dogs and are found in the fibrovascular stroma of the testicle and produce testosterone[5]

Many interstitial cell tumors are non-metastatic but functional tumors are associated with prostatic disease and prostatic hyperplasia, circumanal gland hyperplasia and perianal tumors. Approximately half of affected dogs have both testes affected[6].

Clinical signs are often vague, but a scrotal or inguinal mass can often be palpated.

Diagnosis is based on physical examination, lateral abdominal radiograph, abdominal ultrasonography, histopathology of biopsies[7] or direct examination during exploratory celiotomy. Local and sublumbar lymph nodes should be investigated for metastasis. Ultrasound examination is a sensitive and relatively specific technique for the diagnosis of testicular tumors with interstitial cell tumors appearing as a well-circumscribed mass with predominantly hypoechoic and small hyperechoic areas.

A differential diagnosis would include seminoma, Sertoli cell tumor and feminizing syndrome. Any underlying prostatic disease must be excluded.

Treatment usually requires castration with resection of a large amount of the spermatic cord.

References

  1. Doxsee AL et al (2006) Extratesticular interstitial and Sertoli cell tumors in previously neutered dogs and cats: a report of 17 cases. Can Vet J 47(8):763-766
  2. Grieco V et al (2008) Canine testicular tumours: a study on 232 dogs. J Comp Pathol 138(2-3):86-89
  3. Owston MA & Ramos-Vara JA (2007) Histologic and immunohistochemical characterization of a testicular mixed germ cell sex cord-stromal tumor and a leydig cell tumor in a dog. Vet Pathol 44(6):936-943
  4. Doxsee AL et al (2006) Extratesticular interstitial and Sertoli cell tumors in previously neutered dogs and cats: a report of 17 cases. Can Vet J 47(8):763-766
  5. Papaioannou N et al (2009) Immunohistochemical expression of dog TERT in canine testicular tumours in relation to PCNA, ki67 and p53 expression. Vet Res Commun 33(8):905-919
  6. Kawakami E et al (2007) Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis. J Vet Med Sci 69(12):1259-1262
  7. Masserdotti C et al (2005) Cytologic features of testicular tumours in dog. J Vet Med A Physiol Pathol Clin Med 52(7):339-346