Page 1019 - Small Animal Internal Medicine, 6th Edition

CHAPTER 56 Clinical Conditions of the Dog and Tom 991

a neutered male, whereas a positive AMH test indicates the in adult dogs and cats whose neutering status is unknown or
presence of testes. suspected to be incomplete.
VetBooks.ir confirm the condition in pediatric dogs and cats with unilat- TESTICULAR TORSION
Ultrasound localization of cryptorchid testis(es) can
eral or bilateral involvement, and assist the surgeon in plan-
ning the approach (i.e., inguinal versus cranial abdominal). Other than malignant transformation, the most common
The retained testes can be positioned anywhere between complication of uncorrected cryptorchidism in the dog is
the ipsilateral kidney and the scrotum. The right testis is testicular torsion, which occurs with an increased incidence
more commonly cryptorchid. A systematic evaluation of the in neoplastic intraabdominal testes, and presents as an acute
region from the caudal renal pole to the inguinal canal can abdomen. Ultrasound is commonly performed in dogs with
identify an oval, homogenously echogenic structure with a acute abdominal distress. Cryptorchid testes can be posi-
mildly hyperechoic border representing the parietal and vis- tioned anywhere between the ipsilateral kidney and the
ceral tunics. The epididymis is usually distinctly less echoic inguinal canal, but tend to gravitate to the mid ventral
than the testicular parenchyma, as in the scrotal testis. The abdomen when enlarged. Testicular torsion can appear
cryptorchid testis will maintain the anatomic structure of the similar to orchitis with a diffuse hypoechoic appearance to
mediastinum testis, a hyperechoic slash, and normal testicu- the testis; malignant transformation and gangrenous change
lar echogenicity despite being reduced in size as compared can make their appearance less recognizable (Fig. 56.2, A,
with a scrotal testis (Fig. 56.1, A, 56.1, B, Video 56.1). Ultra- 56.2, B). Doppler examination reveals aberrant blood flow.
sound is also the method of choice to localize cryptorchidism Immediate surgical intervention for removal is indicated.

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FIG 56.1
Testicular ultrasound. (A) Side-by-side image of normal scrotal testes. (B) Sagittal view of
cryptorchid testis (cursors). Note the uniform parenchymal echotexture (similar to the
spleen), mediastinum testis (hyperechoic central linear structure), and relatively smaller size
in the intraabdominal (cryptorchid) testis.

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A B

FIG 56.2
Ultrasound image of an intraabdominal mass. (A) A midabdominal testis (cursors) with
complex echotexture. (B) A Sertoli cell tumor was identified within the enlarged and
torsed intraabdominal testis after exploratory and castration. The normal scrotal testis for
comparison, left.