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Testicular Tumors

Testicular tumors can occur in roosters. The clinical signs that develop are attributable to a space-occupying mass and are often similar in presentation to that seen in birds with renal tumors.
Rooster reproductive system
The two general types of testicular tumors which occur in roosters are germ cell tumors and sex cord-stromal tumors. Germ cell tumors include seminomas, embryonal carcinomas, and teratomas. Sex cord-stromal tumors include Sertoli-cell tumors and Leydig (interstitial) cell tumors. Mixed germ cell–sex cord-stromal tumors have also been reported. These include neoplastic elements derived from both the germ cell and sex cord stromal elements of the testis.

Surgical removal is possible, however there haven't been any reported cases to date involving chickens. Hormone therapy has also showed some success in reducing the size of the tumors, through leuprolide acetate injections or deslorelin acetate (Suprelorin) implants.

Clinical Signs

Progressive weight loss
Changes in behavior
Unilateral paresis
Reduced appetite


  • History
  • Clinical signs
  • Ultrasound

Reported Cases

  • Case 1: Seminoma in a Guinea fowl. An adult guinea fowl's right testis was extremely enlarged and replaced by round and polyhedral pleomorphic neoplastic cells showing nest, sheet, and diffuse growth patterns. The neoplastic cells had acidophilic cytoplasm and hyperchromatic and eccentrically placed nuclei. Metastatic lesions composed of diffuse growth of neoplastic cells similar to those of the primary tumor were seen in the liver, lungs, kidneys, and heart, and neoplastic emboli were often detected within blood vessels of these organs, indicating hematogenous metastasis. Ref
    Primary tumor site: testicleSites of Metastases: liver, lungs, kidney, heart

  • Case 2: Bilateral seminoma in a Cockatiel . An 18-year-old male cockatiel presented with a clinical history of dyspnea, lethargy, and reluctance to perch. Coelomic ultrasonographic examination revealed hypoechoic nodules in the proximity of, and within, the liver. The bird did not respond to supportive care and was euthanatized. At necropsy, the testes were bilaterally enlarged, whitish-tan, firm, and multilobulated. The right hepatic lobe contained a mass that had a similar color and consistency to those in the testes. On histologic and ultrastructural examinations, the diagnosis was bilateral testicular seminoma with hepatic metastasis. Ref
    Primary tumor site: testisSites of Metastases: liver

  • Case 3: Bilateral seminoma in a Eagle. A 30-year-old bald eagle was presented with a history of hyporexia and lethargy. Results of initial hematologic testing, biochemical analysis, and fecal examination were unremarkable, and clinical signs did not resolve with supportive care and management changes. Results of echocardiography, based on auscultation of a murmur, and coelomic endoscopy, based on the presence of a soft tissue opacity on radiographs, as well as an aspergillosis panel were largely unsuccessful in determining a definitive diagnosis. Euthanasia was performed after the eagle did not recover from anesthesia after endoscopy. Necropsy results demonstrated bilateral testicular seminomas with metastases to the ventriculus. Ref
    Primary tumor site: testisSites of Metastases: ventriculus

  • Case 4: Unilateral seminoma in a Duck. The duck's right testis was markedly enlarged. The liver surface showed multifocal to coalescent regular circular umbilicated greyish-white spots. In addition, multiple rough whitish nodules were evident on the pancreas and the visceral peritoneum lining the intestine. Histologically, the right testicular parenchyma was diffusely affected and replaced by neoplastic growth, consisting of sheets of large round to polyhedral cells with conspicuous vesicular nuclei having distinctly granular chromatin and prominent nucleoli. Sheets of cells with similar features were observed also in the other affected organs. Multiple lung metastases were detected on histology. Ref
    Primary tumor site: testicleSites of Metastases: liver, lungs, pancreas, peritoneal

  • Case 5: Unilateral seminoma in a Dove. A 15-year-old domestic rock dove was presented to the Service de Médecine Zoologique of the Université de Montréal with a 10 day history of lethargy and chronic weight loss of 1 year duration. Ultrasonographic evaluation of the coelomic cavity revealed the presence of effusion and a well-defined mass containing variably sized hypoechoic nodules of unknown origin. Cytologic evaluation of fine-needle aspirates of the mass indicated a malignant epithelial tumor consisting of round cells arranged individually and in clusters, with large nuclei, prominent nucleoli, moderate anisocytosis and anisokaryosis, atypical mitoses, occasional binucleation and multinucleation, and large numbers of ruptured cells. A diagnosis of seminoma was established on histologic sections obtained at necropsy. The cytologic features of this tumor were similar to those of canine seminomas except for the presence of lymphocytes, which were not observed in significant numbers in cytologic smears or histologic sections. Ref
    Primary tumor site: testicleSites of Metastases: none

  • Case 6: Sertoli cell tumor in a Duck. A 13 year old male mallard was diagnosed with a non resectable Sertoli cell tumor involving the left testis. The duck was treated with four doses of single agent carboplatin given at 4 to 5 week intervals. Heteropenia, 2 weeks after each treatment, was the acute dose limiting toxicity. The tumor reduced in size by 25%, and the duck's clinical condition improved for 12 months. Ref
    Primary tumor site: testicleSites of Metastases: none

  • Case 7: Sertoli cell tumor in a Goose. At necropsy, in addition to one large tumor mass (15 cm in diameter), multiple small tumor masses were observed over the peritoneum and mesenterium in the coelomic cavity. The large tumor mass was composed of sheets, lobules, and small islands of tumor cells, and elongated tumor cells lying perpendicular to fibrous connective tissue were characteristic. Such histopathologic characteristics were common to all the tumors. The tumor cells were immunohistochemically positive for neuron-specific enolase and S-100, and some tumor cells contained fine intracytoplasmic pigments that stained red by oil red O staining. These findings, taken together with the fact that one testis was markedly atrophied and bore no tumor cells and the other testis was not discernible, the present case was diagnosed as unilateral malignant Sertoli cell tumor arising from the unilateral testis. Ref
    Primary tumor site: testicleSites of Metastases: coelomic cavity

  • Case 8: Teratoma in a Chicken. An 18-month-old rooster started developing signs of anorexia and respiratory disorders. He was admitted to the Veterinary School of Sidi Thabet in Tunisia. A necropsy was performed in order to better understand the cause of death. Firstly, macroscopic examination revealed hypertrophy of both testicles. Consequently, liver, bowels and lungs were compressed by the testicles. Secondly, histological examination report a typical case of testicular teratoma, characterized by mixture tissue elements; consisting of immature and mature well-differentiated tissue. Ref
    Primary tumor site: testisSites of Metastases: liver, intestines, lungs

  • Case 9: Mixed germ cell tumor in a Chicken. A 5-year-old backyard Araucana rooster was presented to the regional diagnostic laboratory with a history of progressive lethargy and respiratory signs. Autopsy revealed a single large mass of testicular origin in the coelomic cavity, causing compression of other organs. Histologically, the mass was 1 neoplasm with mixed components of 2 different germ cell tumors, namely a teratoma composed of elements of all 3 primordial germ cell lines (ectoderm, mesoderm, and endoderm), and a seminoma consisting of round or polygonal cells arranged in sheets supported by a scant fibrovascular stroma. Ref
    Primary tumor site: testicleSites of Metastases: none

  • Case 10: Duck in a Germ cell tumor. A male pekin duck was presented for examination because of respiratory distress and 2- to 3-month history of lameness and lethargy. Results of radiography, ultrasonography, and cytologic examination revealed a large neoplastic mass in the coelom. The duck was euthanatized, and results of necropsy revealed 2 large, lobulated masses in the coelom and a small nodule on the liver. Histopathologic examination of the large masses revealed a collision pattern testicular tumor consisting of Sertoli, seminoma, and interstitial cell components. The hepatic nodule was a metastatic lesion consistent with a Sertoli cell testicular tumor. Ref
    Primary tumor site: testisSites of Metastases: liver


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Hormone therapyLeuprolide acetate injections or deslorelin acetate (Suprelorin) implants.




Scientific References

Age Range

Usually occur in older roosters.

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