Pediatric Appendix Testis Torsion and Appendix Epididymis Torsion

  • Etiology:
    — Testicular appendage can occur in multiple locations along the epididymis and testis and spermatic cord
    — Twisting of appendix testis more common than twisting of appendix epididymis
  • Imaging:
    — Initially hypoechoic to hyperechoic ovoid mass between testes and epididymal head that may have flow early on
    — Epididymis and cord and sometimes testes are reactively swollen and hyperemic
    — Later becomes more echogenic and avascular and eventually becomes a “scrotal pearl”
    — May have reactive hydrocele and scrotal skin thickening
  • DDX: Prepubertal epididymitis
  • Complications: Can cause reactive epididimo-orchitis
  • Treatment: None
  • Clinical:
    — Palpable nodule
    — Blue dot sign in 33%
    — Mimics pain of testicular torsion
    — Most common cause of acute scrotal pain in prepubertal males (31-57%)

Radiology Cases of Appendix Testis Torsion and Appendix Epididymis Torsion

Radiology Cases of Appendix Testis Torsion

US of torsion of the appendix testis
Transverse (above) and sagittal (below) US of the left testicle shows a round, mixed echogenicity lesion superior and medial to the left testicle that had no flow on color and spectral doppler US. The left epididymis and left testicle were normal in appearance with normal appearing blood flow.

Radiology Cases of Appendix Epididymis Torsion