History
A 6-year-old neutered male Cocker Spaniel was evaluated because of pruritic erythematous skin and gynecomastia for 2 months. The dog was neutered at 10 months of age and was reportedly cryptorchid with a physically normal left testicle and an intra-abdominal right testicle that was removed by laparotomy. On physical examination, all mammary glands were enlarged and there was a palpable mass in the midabdomen. Computed tomography of the abdomen was performed (Figure 1).
Transverse CT image of the midabdomen of a 6-year-old neutered male Cocker Spaniel evaluated because of pruritic erythematous skin and gynecomastia of 2 months’ duration. On physical examination, the dog had a palpable abdominal mass. The CT image was obtained immediately after IV injection of contrast medium (standard algorithm; window width, 400 Hounsfield units; window level, 40 Hounsfield units; slice thickness, 2.5 mm).
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Transverse CT image of the midabdomen of a 6-year-old neutered male Cocker Spaniel evaluated because of pruritic erythematous skin and gynecomastia of 2 months’ duration. On physical examination, the dog had a palpable abdominal mass. The CT image was obtained immediately after IV injection of contrast medium (standard algorithm; window width, 400 Hounsfield units; window level, 40 Hounsfield units; slice thickness, 2.5 mm).
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Transverse CT image of the midabdomen of a 6-year-old neutered male Cocker Spaniel evaluated because of pruritic erythematous skin and gynecomastia of 2 months’ duration. On physical examination, the dog had a palpable abdominal mass. The CT image was obtained immediately after IV injection of contrast medium (standard algorithm; window width, 400 Hounsfield units; window level, 40 Hounsfield units; slice thickness, 2.5 mm).
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Same CT image as Figure 1. The mass (M) lies in the midabdomen to the right of midline at the level of the caudal pole of the left kidney (LK) and the tail of the spleen (S). The brightness of the aorta (large arrowhead) but not the caudal vena cava (small arrowhead) indicates this image was obtained immediately after IV injection of contrast medium. Note the discrete collection of small tortuous vessels (arrows) on the dorsal aspect of the mass (M) that is characteristic of the pampiniform plexus of the testicle.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Same CT image as Figure 1. The mass (M) lies in the midabdomen to the right of midline at the level of the caudal pole of the left kidney (LK) and the tail of the spleen (S). The brightness of the aorta (large arrowhead) but not the caudal vena cava (small arrowhead) indicates this image was obtained immediately after IV injection of contrast medium. Note the discrete collection of small tortuous vessels (arrows) on the dorsal aspect of the mass (M) that is characteristic of the pampiniform plexus of the testicle.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Same CT image as Figure 1. The mass (M) lies in the midabdomen to the right of midline at the level of the caudal pole of the left kidney (LK) and the tail of the spleen (S). The brightness of the aorta (large arrowhead) but not the caudal vena cava (small arrowhead) indicates this image was obtained immediately after IV injection of contrast medium. Note the discrete collection of small tortuous vessels (arrows) on the dorsal aspect of the mass (M) that is characteristic of the pampiniform plexus of the testicle.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Curved planar reconstruction (close to sagittal plane) CT image of the dog in Figure 1. Note the vascular anatomy of the mass (M) including the origin of the testicular artery (arrowheads) at the aorta (Ao). B = Bladder. P = Prostate.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Curved planar reconstruction (close to sagittal plane) CT image of the dog in Figure 1. Note the vascular anatomy of the mass (M) including the origin of the testicular artery (arrowheads) at the aorta (Ao). B = Bladder. P = Prostate.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Curved planar reconstruction (close to sagittal plane) CT image of the dog in Figure 1. Note the vascular anatomy of the mass (M) including the origin of the testicular artery (arrowheads) at the aorta (Ao). B = Bladder. P = Prostate.
Citation: Journal of the American Veterinary Medical Association 246, 11; 10.2460/javma.246.11.1183
Diagnostic Imaging Findings and Interpretation
A globoid, well-marginated, soft tissue–attenuating mass measuring approximately 7 × 5 cm is evident in the midabdomen to the right of midline at the level of the caudal pole of the left kidney and the tail of the spleen (Figures 2 and 3). A discrete collection of small tortuous vessels is visible on the dorsal aspect of the mass and is characteristic of the pampiniform plexus of the testicle. Hence, this mass represents an intra-abdominal testicle. The marked enlargement of the testicle and globoid shape are compatible with neoplastic transformation. Thoracic CT revealed no signs of pulmonary metastasis.
Treatment and Outcome
Serum estradiol concentration was high (30 pg/mL); a serum estradiol concentration > 15 pg/mL is suggestive of a Sertoli cell tumor. The mass was removed surgically. The gross anatomic features of the mass were consistent with an enlarged testicle. No evidence of intra-abdominal metastasis was identified. Histologic findings confirmed the mass was a Sertoli cell tumor. Removal of the neoplastic testicle resolved clinical signs in the dog.
Comments
Cryptorchidism is a well-recognized testicular developmental disorder.1 In dogs, right-sided inguinal cryptorchidism is the most common form, followed by right-sided abdominal cryptorchidism.2 Maldescended testicles develop a variety of histologic abnormalities in young dogs3 and are associated with an increased risk of neoplasia in later life.4,5 Neoplasms occurring in maldescended testicles may behave more aggressively than tumors occurring in scrotal testicles.4 Testicular tumors that produce estrogen or estradiol cause a feminizing paraneoplastic syndrome characterized by nonpruritic bilaterally symmetric alopecia, hyperpigmentation, gynecomastia, edematous and pendulous penile sheath, prostatic dysfunction, attraction to other male dogs, and standing in a female posture to urinate.1 Sertoli cell tumors are the testicular tumor most often associated with feminization in male dogs.1 Distant metastasis of Sertoli cell tumors occurs in < 15% dogs4; hence, removal of a neoplastic testicle is often curative. Persistence or recurrence of clinical signs of feminization would suggest another source of hormone production as a result of metastasis.
Abdominal masses in dogs, including suspected maldescended testicles, are investigated more often by radiography or ultrasonography than by CT. Regardless of the imaging modality used, ability to differentiate types of abdominal masses depends primarily on recognition of specific anatomic features, including location with respect to adjacent organs, vascular supply, and internal features. Abdominally retained testicles usually occur in the caudoventral aspect of the abdomen and are small and oval, with a central mediastinum that is visible ultrasonographically.6 Enlargement, a change in shape from oval to globoid, loss of the mediastinum, and heterogeneous echotexture are signs of neoplasia.6 Additionally, swelling of the spermatic cord suggests testicular torsion.7,8 In the dog of the present report, the pampiniform plexus was considered a characteristic anatomic feature that identified the mass as testicular. The marked enlargement and globoid shape of the testicle supported a diagnosis of neoplasia, but there was no swelling of the spermatic cord or altered vascularity to suggest torsion.
Clearly, the neutering history in the dog of the present report was erroneous. It is doubtful that removal of an intra-abdominal structure had been attempted because no laparotomy scar was visible. Alternatively, it is possible that removal of the retained testicle was advised but not done.
1. Feldman EC, Nelson RW, eds. Canine and feline endocrinology and reproduction. 3rd ed. Philadelphia: Saunders, 2004;961–963.
2. Yates D, Hayes G, Heffernan M, et al. Incidence of cryptorchidism in dogs and cats. Vet Rec 2003; 152:502–504.
3. Veronesi MC, Riccardi E, Rota A, et al. Characteristics of cryptic/ectopic and contralateral scrotal testes in dogs between 1 and 2 years of age. Theriogenology 2009; 72:969–977.
4. Hayes HM Jr, Wilson GP, Pendergrass TW, et al. Canine cryptorchism and subsequent testicular neoplasia: case-control study with epidemiologic update. Teratology 1985; 32:51–56.
5. Liao AT, Chu PY, Yeh LS, et al. A 12-year retrospective study of canine testicular tumors. J Vet Med Sci 2009; 71:919–923.
6. Pugh CR, Konde LJ. Sonographic evaluation of canine testicular and scrotal abnormalities: a review of 26 cases. Vet Radiol 1991; 32:243–250.
7. Gradner G, Dederichs D, Hittmair KM. Intra-abdominal testicular torsion in a cryptorchid dog. Wien Tierarztl Monatsschr 2004; 93:58–61.
8. Hecht S, King R, Tidwell AS, et al. Ultrasound diagnosis: intra-abdominal torsion of a non-neoplastic testicle in a cryptorchid dog. Vet Radiol Ultrasound 2004; 45:58–61.
