[Inguinal and Scrotal Diseases in Children and Adolescents]

Abstract

In children and adolescents, inguinal and scrotal diseases are relatively common, and imaging is very useful for the diagnosis and differential diagnosis of these diseases. Therefore, it is important to understand the imaging findings of these diseases. In this article, we classify these diseases into small testes, cryptorchidism, patent processus vaginalis, acute scrotum pain, trauma, testicular tumors, and others and describe their characteristic findings.

Fig. 1. Diagram of the course of testicular descent.

A. Between the 7th and 12th weeks of gestation, gubernaculum shortening pulls the testes to the deep inguinal ring; in addition, the processus vaginalis develops along the route formed by the gubernaculum and herniates through the abdominal wall. B. At 26–28 weeks of gestation, the testes and processus vaginalis begin to pass through the inguinal canal, and it takes 2–3 days for the testes to reach the scrotum. C. At 32–40 weeks of gestation, there is gradual obliteration of the processus vaginalis, and the patent scrotal portion of the processus vaginalis forms the tunica vaginalis.

Fig. 2. Testicular volume according to age.

The testicular volume is slowly increased at prepubertal age and then is abruptly increased at puberty. A. In the US of a 30-month-old boy, the testicular volume is 0.59 mL. B. In the US of an 11-year-old boy, the testicular volume is 0.84 mL. C. In the US of a 13-year-old boy, the testicular volume is 7.06 mL.

Fig. 3. US shows inhomogeneous echogenicity in the smaller left testis of a 20-year-old male with a history of mump orchitis 4 years prior.

Fig. 4. Testicular atrophy by testicular torsion in a 12-year-old boy.

A. Preoperative US shows avascular inhomogeneous testis. B. US on the 18th day of detorsion shows some vascularity in the testis. C. US after 11 years shows the testis markedly decreased in size.

Fig. 5. Various locations of undescended testis.

A. The undescended left testis in the inguinal area. B. The undescended testis (T) located at the inguinal canal is combined with hydrocele (*). C. The undescended testis in the peritoneal cavity proximal to the inguinal canal shows homogeneous echogenicity with central hyperechoic line (arrowhead) representing mediastinum testis.

Fig. 6. Undescended testis in a 14-year-old boy.

A-C. Axial (A) and coronal reformatted (B) CT and US (C) images show the undescended right testis (arrows) with diffuse punctate calcification in the peritoneal cavity, proximal to the inguinal canal.

Fig. 7. Inguinal hernia in a 6-year-old boy.

A. Initial longitudinal US shows fluid collection (*) in the inguinal area. B. Herniation of the omentum (**) is followed by increased abdominal pressure during ultrasonography.

Fig. 8. US findings of inguinal hernia.

A. Longitudinal US shows gas containing bowels (arrows) and fluid (*) in the herniated sac. B. The herniated sac contains collapsed bowels (arrows).

Fig. 9. Diagram of the non-communicating hydrocele and communicating hydrocele.

A. Non-communicating hydrocele shows a fluid collection without abnormal connection with the peritoneal cavity and normal obliteration of the processus vaginalis. B. Communicating hydrocele shows communication of fluid between the peritoneal cavity and the scrotum due to patency of the processus vaginalis.

Fig. 10. Hydrocele in a 1-year-old boy.

Longitudinal US shows anechoic fluid collection (*) between the visceral and parietal layers of the tunica vaginalis, surrounding testis (T), and epididymis (E). Hydrocele by the patent processus vaginalis is known as congenital hydrocele.

Fig. 11. Acquired hydrocele in a 2-year-old boy.

A. Longitudinal US shows increased vascularity of the testis and epididymis, and it is diagnosed as acute epididymo-orchitis. B. A multiseptated hydrocele (*) is adjacent to the testis.

Fig. 12. Diagram of the funicular hydrocele and encysted hydrocele.

A. Funicular hydrocele shows a fluid collection along the spermatic cord. Fluid collection communicates with the peritoneal cavity but not with the scrotum. B. Encysted hydrocele shows a non-communicating fluid collection trapped in the remnant processus vaginalis.

Fig. 13. Hydrocele of the spermatic cord in a 2-year-old boy.

Longitudinal US shows communicating hydrocele (*) confined to the inguinal area and separated from and above the testis (T), without extending into the scrotum.

Fig. 14. Incarcerated ovarian herniation of the canal of Nuck in a 5-month-old girl.

A, B. Non-contrast (A) and contrast-enhanced (B) axial CT images show herniated left ovary and adnexa (arrows) with high attenuation, suggesting hemorrhagic necrosis caused by incarceration. C. Contrast-enhanced reformatted oblique coronal CT image shows a non-enhancing left ovary (arrow) with peripheral rim enhancement and displaced uterus (open arrow) to the left side.

Fig. 15. Acute epididymitis in a 4-year-old boy.

A, B. Grayscale longitudinal US (A) and color Doppler (B) images show diffusely enlarged EH, body EB, and tail ET with markedly increased vascularity. EB = epididymal body, EH = epididymal head, ET = epididymal tail, T = testis

Fig. 16. Testicular intravaginal torsion in a 10-year-old boy.

Transverse US shows a homogeneously enlarged left testis (T) with decreased vascularity, compared with the right testis. Twisted testes were saved during surgical exploration.

Fig. 17. Testicular intravaginal torsion in a 15-year-old boy.

The testis (T) is enlarged with inhomogeneous echogenicity and non-visualized vascularity. The torsed testis was unable to be saved during surgical exploration.

Fig. 18. Testicular extravaginal torsion in a 6-day-old boy.

The twisted testes were not viable during surgical exploration. Color Doppler imaging shows an irregularly shaped testis (T) with inhomogeneous echogenicity and non-visualized vascularity. The peripheral hyperechoic rim (arrowheads) represents calcification of the tunica vaginalis, suggesting prenatal testicular torsion.

Fig. 19. Normal testicular appendix in a 1-month-old boy.

Longitudinal US shows the normal testis appendix (arrow) as a round structure that is isoechoic with the testis. It is located between the epididymal head (E) and testis (T).

Fig. 20. Torsion of the testicular appendix in an 11-year-old boy with acute scrotal pain by trauma.

Color Doppler image shows an avascular complex mass (arrow) separating from the testis (T). This was confirmed by exploration of torsion of the testicular appendix. E = epididymis

Fig. 21. Torsion of epididymal appendix in an 11-year-old boy with scrotal pain.

Longitudinal US shows an inhomogeneous hyperechoic mass (arrow) at the epididymal head portion above the testis (T). This was confirmed by exploration of the torsion of the epididymal appendix.

Fig. 22. Mixed embryonal carcinoma and immature teratoma in a 17-year-old boy.

A. US shows inhomogeneous masses in the testes. B. CT shows metastatic lymph nodes (arrows) in the para-aortic areas.

Fig. 23. Epididymal cyst in a 10-year-old boy.

Longitudinal US shows an anechoic epididymal cyst (arrow) in the epididymal head (E). T = testis

Fig. 24. Epidermoid cyst in an 11-year-old boy.

US shows three hypo- and hyperechoic nodules with echogenic rim (arrows).

Fig. 25. Varicocele in a 15-year-old boy.

A. Longitudinal US shows multiple anechoic structures in the supratesticular area. B. Color Doppler image shows vascular structures next to the testis.

Fig. 26. US shows multiple tiny non-shadowing hyperechoic foci in the testicle of a 15-year-old boy with microlithiasis.

Fig. 27. US shows a small mobile hyperechoic extratesticular lesion with posterior acoustic shadowing (arrow) in the scrotum of a 1-year-old boy with scrotal calculi.