Torsion of the Appendices and Epididymis
- Author: Jason S Chang, MD; Chief Editor: Erik D Schraga, MD more...
Torsion of testicular appendages can result in the clinical presentation of acute scrotum. Two such appendages are the appendix testis, a remnant of the paramesonephric (müllerian) duct, and the appendix epididymis, a remnant of the mesonephric (wolffian) duct.
The appendix testis is present in 92% of all testes and is usually located at the superior testicular pole in the groove between the testicle and the epididymis. The appendix epididymis is present in 23% of testes and usually projects from the head of the epididymis, but its location may vary. Most acute presentations of scrotal pain and swelling can be attributed to epididymitis, testicular torsion, or torsion of a testicular appendage. The presentations of these conditions can typically be distinguished by history and examination. However, in many cases, torsion of a testicular appendage, although a benign condition, may present identically to testicular torsion, a true urologic emergency.
The vestigial tissues forming the appendices are commonly pedunculated and are structurally predisposed to torsion. Torsion of an appendage leads to ischemia and infarction. Necrosis of appendices causes pain and local inflammation of surrounding the tunica vaginalis and epididymis (acute hemiscrotum). Torsion of the testicular appendage may also be accompanied by presence of a thickened scrotal wall, a reactive hydrocele, and enlargement of the head of the epididymis.
Torsion of testicular appendices is one of the most common causes of acute scrotum; it is the leading cause of acute scrotum in children.
In several retrospective reviews of pediatric patients who presented to the emergency department with acute scrotal pain, the incidence of torsed testicular appendage ranged from 46-71% and represented the most common cause of scrotal pain.
In one study of 155 scrotal explorations that were performed for acute scrotal pain, the pathology was testicular torsion in 46.5% (N = 72); torsion of a testicular appendage in 30.3% (N = 47); epididymitis in 16.1% (N = 25); no obvious pathology in 3.3% (N = 5); and other pathology in 4%. The mean age was 9.1 years (range 0-15 years), and there was a significant difference in age of presentation between those with testicular torsion and those with torsion of a testicular appendage (9 vs 10 years, P = 0.0074). In another, retrospective study of 76 patients younger than 15 years with acute scrotal pain, 59 (78%) had acute spermatic cord torsion, 16 (21%) had torsion of the testicular appendage, and 1 (1%) had orchitis. In patients with acute spermatic cord torsion, the median age was 13 years (range: 0.18-14.97).
Torsion of the testicular appendices is virtually a benign condition, but again, must be distinguished from testicular torsion, which can have permanent consequences on testicular viability.
Necrotic tissue is reabsorbed without any sequelae in almost all cases.
The literature contains only one case report of a scrotal abscess secondary to tissue necrosis.
Some cases of persistent pain due to torsion of the testicular appendix have required surgical excision for relief or often for diagnostic surgical exploration.
Little evidence supports the suggestion that scrotal calculi can form because of calcification of the necrotic appendix.
A retrospective study by Rakha et al demonstrated no evidence of any bacterial or fungal infection in 79 cases of torsion of the testicular appendage. Histologic analysis showed no correlation between degree of inflammatory infiltrate and pyogenic infection. 
Greatest morbidity results from a missed diagnosis of testicular torsion and a subsequent delay in treatment.
Age ranges vary from infancy to adulthood with more than 80% of cases occurring in children aged 7-14 years. Mean age is 10.6 years. This condition rarely presents in adulthood (probably due to local fibrosis). Torsion of testicular appendices is the leading cause of acute scrotum in children.
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