Diagnostic Ultrasound - Abdomen and Pelvis

Tubular Ectasia of Rete Testis
TERMINOLOGY
Synonyms
• Dilated rete testis
• Cystic transformation of rete testis
IMAGING
General Features
• Best diagnostic clue
○ Variably sized network of dilated tubules near
mediastinum testis with no flow on color Doppler
• Location
○ Posterior near mediastinum testis
○ Frequently bilateral
• Size
○ Can replace large portion of normal parenchyma
○ Variably sized cystic spaces
• Morphology
○ Branching tubules converging at mediastinum testis
○ Characteristic appearance and location make it possible
to distinguish this benign condition from malignancy
Ultrasonographic Findings
• Grayscale ultrasound
○ Longitudinal plane shows branching tubular structures
along mediastinum
– Dilated tubules create lace-like or "fishnet"
appearance
○ Adjacent parenchyma is normal
– Differentiates it from cystic malignant masses, which
have abnormal rind of parenchyma
○ Associated ipsilateral spermatoceles are common
– May also see intratesticular cysts
• Color Doppler
○ Tubules are avascular and fluid filled, hence no color flow
○ Normal flow in adjacent testicular parenchyma
MR Findings
• MR performed for confirmation if cystic malignant
neoplasm cannot be ruled out
• T1 and proton density-weighted Images: Hypointense to
testis
• T2WI: Iso- to hyperintense to testis → nearly invisible
○ Malignant testicular neoplasms → solid portions
hypointense on T2WI; have dark fibrous capsule
Imaging Recommendations
• Best imaging tool
○ High-resolution US (≥ 7.5 MHz) is imaging modality of
choice
• Protocol advice
○ Longitudinal plane shows morphology of tubules far
better than transverse plane
– Appears more mass-like and has greater likelihood of
causing confusion when viewed in transverse plane
○ Always use color Doppler to look for areas of abnormal
parenchymal flow
DIFFERENTIAL DIAGNOSIS
Testicular Carcinoma
• Mixed germ cell tumors with teratomatous components
will often have cystic areas
• Does not form network of tubules
• Surrounding parenchyma is abnormal
○ Will have abnormal flow on color Doppler
Intratesticular Varicocele
• Multiple intratesticular anechoic serpiginous tubules with
characteristic color flow on Doppler, particularly during
Valsalva maneuver
• Will have associated extratesticular varicocele
Testicular Infarct
• Avascular hypoechoic mass, as sequelae of any previous
vascular insult
• Sharp, linear borders demarcate area
PATHOLOGY
General Features
• Etiology
○ Partial or complete efferent ductule obstruction →
ectasia → eventually cystic transformation
○ May be associated with epididymal obstruction due to
inflammation or trauma
• Associated abnormalities
○ Spermatocele
○ Epididymal cyst
○ Intratesticular cyst
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Generally nonpalpable and asymptomatic
○ May be found when doing ultrasound for related issue,
such as epididymal cyst or spermatocele
Demographics
• Age
○ Middle-aged to elderly men most commonly affected
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Important to distinguish tubular ectasia from malignancy to
prevent unnecessary orchiectomy
SELECTED REFERENCES
1. Bhatt S et al: Imaging of non-neoplastic intratesticular masses. Diagn Interv
Radiol. 2011 Mar;17(1):52-63. Epub 2010 Jun 30. Review. Erratum in: Diagn
Interv Radiol. 17(4):388, 2011
2. Bhatt S et al: Sonography of benign intrascrotal lesions. Ultrasound Q.
22(2):121-36, 2006
3. Woodward PJ et al: From the archives of the AFIP: tumors and tumorlike
lesions of the testis: radiologic-pathologic correlation. Radiographics.
22(1):189-216, 2002
4. Dogra VS et al: Benign intratesticular cystic lesions: US features.
Radiographics. 21 Spec No:S273-81, 2001
5. Tartar VM et al: Tubular ectasia of the testicle: sonographic and MR imaging
appearance. AJR Am J Roentgenol. 160(3):539-42, 1993
Diagnoses: Scrotum
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