Diagnostic Ultrasound - Abdomen and Pelvis

Undescended Testis
TERMINOLOGY
Synonyms
• Cryptorchidism, cryptorchism
Definitions
• Incomplete descent of testis into base of scrotum
IMAGING
General Features
• Best diagnostic clue
○ Unilateral or bilateral absence of testis in scrotum
• Location
○ Anywhere from kidney to inguinal canal, inguinal canal
most common (80%)
○ Bilateral in 10%
○ Unilateral more common on right (70%)
Ultrasonographic Findings
• Grayscale ultrasound
○ Absence of testicle/spermatic cord within scrotal sac
○ Ovoid homogeneous, less echogenic, well-circumscribed
structure smaller than normal descended testis
– Identify echogenic line of the mediastinum testis to
distinguish cryptorchid testis from other inguinal
masses on US
– Lack of surrounding fluid and compression by
adjacent structures make the testicular margins less
defined than normally located testes
– Testes < 1 cm cannot be detected
○ Undescended testis in adults exhibit different degrees of
atrophy with altered parenchymal echogenicity
○ Associated with microlithiasis; neoplastic foci, if present
may be detected
MR Findings
• MR imaging should be used in US-negative cases
• T1WI: Low signal intensity ovoid mass; T2WI: High signal
intensity ovoid mass
DIFFERENTIAL DIAGNOSIS
Inguinal Lymphadenopathy
• Most common groin "mass" seen in multiple pathologies
Inguinal Hernia
• Direct/indirect inguinal hernia, bowel/omentum as hernia
content
Anorchia: Absent Testis
• Congenital or prior resection
PATHOLOGY
General Features
• Etiology
○ Interruption of embryologic testicular descent from
abdomen into scrotal sac
• Associated abnormalities
○ Renal agenesis/ectopia, prune belly syndrome,
hypospadias
Staging, Grading, & Classification
• Undescended testis: Arrest of testis along its normal path
of descent
○ Abdomen, inguinal canal, external inguinal ring,
prescrotal, upper scrotal
○ 80% palpable, 20% unpalpable
• Ectopic testis: Testis located outside its normal path of
descent
○ Superficial inguinal pouch, perineal, perirenal, thigh
CLINICAL ISSUES
Demographics
• Epidemiology
○ Testis may be absent from scrotum in 4% of newborns
(spontaneous descent in 1st few months)
○ More common in preterm infants
Natural History & Prognosis
• Complications
○ Cancer: Incidence is 1:1,000-1:2,500
– 5-7x ↑ risk of malignant neoplasm in cryptorchid
testis; ~ 20% of tumors occur in the contralateral
descended testis (also at an increased risk)
– Untreated UDT → seminoma is most common tumor
– UDT treated with orchiopexy → nonseminomatous
tumors more common (such as embryonal)
○ Torsion
○ Atrophy/infertility: Infertility more common with
bilateral UDT
○ Trauma
Treatment
• Orchiopexy before age 2 to preserve fertility
○ Prepubertal males (≤ 12 years) who undergo orchiopexy
have 2-6x decreased relative risk of developing testicular
cancer compared to patients who undergo orchiopexy
after age 12
• Orchiectomy
○ Consider in patients aged 12-50 years
○ Biopsy can be performed in patients ≥ 10 years to
determine if orchiectomy is indicated
SELECTED REFERENCES
1. Abacı A et al: Epidemiology, classification and management of undescended
testes: does medication have value in its treatment? J Clin Res Pediatr
Endocrinol. 5(2):65-72, 2013
2. Ekenze SO et al: The utility of ultrasonography in the management of
undescended testis in a developing country. World J Surg. 37(5):1121-4,
2013
3. Singal AK et al: Undescended testis and torsion: is the risk understated? Arch
Dis Child. 98(1):77-9, 2013
4. Abbas TO et al: Role of ultrasonography in the preoperative assessment of
impalpable testes: a single center experience. ISRN Urol. 2012:560216, 2012
5. Canning DA: Re: Diagnostic performance of ultrasound in nonpalpable
cryptorchidism: a systematic review and meta-analysis. J Urol. 187(4):1434,
2012
6. Mansour SM et al: Does MRI add to ultrasound in the assessment of
disorders of sex development? Eur J Radiol. 81(9):2403-10, 2012
7. Tasian GE et al: Diagnostic imaging in cryptorchidism: utility, indications, and
effectiveness. J Pediatr Surg. 46(12):2406-13, 2011
8. Tasian GE et al: Imaging use and cryptorchidism: determinants of practice
patterns. J Urol. 185(5):1882-7, 2011
9. Nguyen HT et al: Cryptorchidism: strategies in detection. Eur Radiol.
9(2):336-43, 1999
Diagnoses: Scrotum
705