Appendix Testis Torsion

Torsion of the testicular appendages is considered the most common cause of acute scrotal pain in prepubertal children and may even be the single most prevalent cause of pediatric orchalgia. Therefore, it should be included in the differential diagnosis for any male presenting with an acute scrotum, particularly in the pediatric age group. Two testicular appendages can undergo torsion and become symptomatic: the appendix testis and the appendix epididymis.  The appendix testis, sometimes called hydatid of Morgagni, is a vestigial remnant of the Mullerian duct and is present in 76% to 83% of testes. When present, it is located on the superior pole of the testicle between the testis and epididymis and is the most common testicular appendage to undergo torsion. It is homologous to the female's fimbriated end of the Fallopian tube. The appendix epididymis is a vestigial Wolffian (mesonephric) duct remnant in 22% to 28% of testes. When present, it occurs along the head of the epididymis. It is sometimes considered to be a detached efferent epididymal duct.