Citation, DOI and article data
Epididymal appendices, also known as appendix of the epididymis or appendix epididymis, are an testicular appendage found at the head of the epididymis 1. They represent a developmental remnant of the mesonephric duct (Wolffian duct). In 78% of the cases, it has a stalk configuration and is thus prone to torsion 2.
Normally, epididymal appendices are of no clinical significance, but when torsed they can cause an acute scrotum in children 2. After torsion of its pedicle with resultant infarction, the appendage may detach and wander inside the scrotum and appear as minute mobile particles ("loose bodies") 3.
Ultrasonography with a high-frequency linear transducer can reliably evaluate the appendix testis, including its vascularity. Its reported frequency in ultrasonography is ~12.5% (range 6-17%) 3.
The appendix epididymis, similarly to the appendix testis, is normally oval and pedunculated, although may be sessile in shape 1. They appear iso- or hyperechoic to the epididymal parenchyma. Sometimes, calcifications may be found. In general, the epididymis appendix is best seen when floating in a hydrocele.
When torsed, it is a cause of acute scrotum and imaging differential diagnosis should include:
- 1. Sellars ME, Sidhu PS. Ultrasound appearances of the testicular appendages: pictorial review. Eur Radiol. 2003;13 (1): 127-35. doi:10.1007/s00330-002-1387-1 - Pubmed citation
- 2. Baldisserotto M, de Souza JC, Pertence AP et-al. Color Doppler sonography of normal and torsed testicular appendages in children. AJR Am J Roentgenol. 2005;184 (4): 1287-92. doi:10.2214/ajr.184.4.01841287 - Pubmed citation
- 3. Valentino M, Bertolotto M, Ruggirello M et-al. Cystic lesions and scrotal fluid collections in adults: Ultrasound findings. J Ultrasound. 2011;14 (4): 208-15. doi:10.1016/j.jus.2011.10.008 - Free text at pubmed - Pubmed citation