IS Case 292: Torsion of the testicular appendix

Richard Gong, MD

Imaging Sciences URMC 2009
Publication Date: 2009-08-05


An 11-year-old boy presented to the emergency department with acute right scrotal pain. Clinical concern was for testicular torsion.


Ultrasound images revealed normal bilateral testes with normal color flow (not shown). In addition, a hypovascular, hypoechoic structure was seen adjacent to the normal right epididymis and right testis.


Torsion of the testicular appendix


Torsion of the testicular appendix is a common cause of acute scrotal pain and can mimic testicular torsion clinically. Torsion of the testicular appendices (appendix testis and appendix epididymis) is the leading cause of acute scrotal pain in children. More than 80% of cases occur in children ages 7 to 14 and it is rare in adulthood.

The twisted appendix can be evident clinically as a para-testicular nodule at the superior aspect of the testicle. This "blue dot" sign is present in only approximately 21% of cases, but is considered pathognomonic. The presence of a blue dot sign, clear palpable underlying abnormality and non-tender testis can exclude testicular torsion on clinical ground alone.

With ultrasonography, the twisted appendix can be seen as an avascular hypoechoic mass adjacent to the normally perfused testis and surrounded by an area of increased Doppler perfusion. However, the twisted appendix can be seen as an echogenic extratesticular mass situated between the head of the epididymis and the upper pole of the testis.

Necrotic tissue of the torsed testicular appendix causes no other damage than to itself; therefore, treatment is usually conservative with NSAIDs and ice. The pain usually resolves in one week, but may persist for several weeks. In rare cases, uncontrolled pain can be treated with surgical excision of the testicular appendix.


  1. Rumack CM, Wilson SR, Charboneau JW. Diagnostic Ultrasound. 3rd ed. St. Louis: Elsevier Mosby, 2005.
  2. Chang JS. Torsion of the appendices and epididymis. E-medicine. Mar 24, 2009.

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