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.

US of torsion of the appendix testis — Sagittal US of the left scrotum at presentation (above) shows a round lesion of heterogenous echogenicity superior to the left testicle. Sagittal US of the left scrotum 2 weeks later (below) shows the lesion has decreased in size and become uniformly echogenic.

Radiology Cases of Appendix Epididymis Torsion

US of torsion of the appendix epididymis — Sagittal US of the scrotum on the day of presentation (above) shows a hypoechoic oval lesion in the epididymis just above the testicle. Sagittal US of the scrotum 2 weeks later (below) shows the previously seen hypoechoic lesion in the epididymis to have evolved into an anechoic cyst.