Torsion of the testicular appendages: sonographic appearance

Torsion of the testis and torsion of the testicular appendages have similar presenting features, namely, acute testicular pain and swelling. The former condition requires urgent surgical intervention to save the testis; the latter condition can be treated conservatively. Despite the frequency of torsion of the appendix testis, which is the most common cause of acute hemiscrotum in the child, only occasional references to this entity are found in the radiological literature. We describe five cases in which an enlarged, homogeneously echogenic appendix testis was seen medial or posterior to the head of the epididymis. All cases were accompanied by hydrocele and thickening of the scrotal wall. Among the five cases, enlargement of the head of the epididymis was seen in four and increased testicular blood flow in two. Scanning in the coronal and transverse planes above the testis was useful in locating the enlarged, twisted appendix.