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Answer

C. Extravaginal Testicular Torsion

Testicular torsion is a medical emergency in which the vascular supply of the testis is compromised to such a degree that ischemic injury ensues. Torsion is typically observed in patients aged 12–18 years due to the rapid growth of the testis during this time period; ischemic damage can occur in as little as 4–6 hours depending on the degree of twist of the spermatic cord. It should be noted, however, that torsion can occur at any age, including in the unborn fetus. Two main types of torsion have been described: extravaginal and intravaginal. Intravaginal torsion is the most common form (65–80 percent) and involves twisting of the spermatic cord inside of the tunica vaginalis. The etiology is described as a “bell clapper deformity” in which the testis is freely suspended within the tunica vaginalis due to improper fixation and can thus rotate about its axis twisting the spermatic cord within the tunica vaginalis. Extravaginal torsion is a less common form of torsion which can occur even months before birth and is most common in neonates. The pathology involves an immature anastomosis of the tunica vaginalis to the scrotal wall via the gubernaculum which results in twisting of the tunica vaginalis and the spermatic cord as a unit. In extravaginal torsion, the testis is enlarged, firm, and nontender with discoloration of the scrotum on the affected side. In contrast, intravaginal torsion is an extremely painful event. 

Color Doppler scrotal ultrasound is the imaging modality of choice for both acute and chronic scrotal pathology. In this patient, scrotal ultrasound reveals abnormal enlargement of the left testis without appreciable blood flow on Doppler and with diffuse heterogeneity of the echotexture; the transverse scrotal view allows for direct comparison to the contralateral testis which demonstrates homogeneous echotexture and robust blood flow (Figure 1). The patient was found to have bilateral hydroceles on ultrasound and 720 degree extravaginal torsion with frank necrosis of the entire left testis on exploration. Emergent scrotal exploration is the hallmark of treatment for ultrasound findings concerning for torsion, as time is of the essence if the viability of the testis is to be preserved. Treatment involves exploration, evaluation of the affected testis, and either orchiectomy for the nonviable testis or orchidopexy if the surgeon has intervened before necrosis has occurred. The contralateral hemiscrotum should also be explored and orchidopexy should be performed as a preventive measure to protect the patient’s future fertility.

Incarcerated inguinal hernia is unlikely given the patient’s exam findings and imaging. The two different types of inguinal hernias, direct and indirect, can lead to complications both of the GI system due to necrosis and obstruction and of the testis due to compressive ischemia of the testicular blood supply. Recall that the defect in an indirect hernia lies in the deep inguinal ring and originates lateral to the inferior epigastric artery. A direct hernia is due to a defect in the abdominal wall medial to the inferior epigastric artery and lateral to the conjoint tendon. Ultrasound would show herniation of abdominal contents parallel to the spermatic cord and exiting the superficial inguinal ring (indirect) or protruding outward from the abdominal wall in Hesselbach’s triangle (direct). 

Hematocele secondary to birth trauma is unlikely as the patient was delivered via cesarean section and no mention was made of a complicated delivery. Ultrasound of a hematocele would likely show homogeneity of the echotexture of the testis with a complex fluid collection occupying the space separating the visceral and parietal layers of the tunica vaginalis. Fibrinous septations may also be noted. Over time, hematoceles become more hypoechoic and may exhibit fluid-fluid levels as well, particularly if chronic in nature. 

Dr. Stanley Zaslau, professor and chief urology residency program director at West Virginia University’s Division of Urology, is the series editor of new Shelf Life titles in surgery, pediatrics, and OB-Gyn.