Sonography of the Pediatric Scrotum: Emphasis on the Ts Torsion, Trauma, and Tumors

Pediatric Imaging Clinical Perspective Sung et al. Ultrasound of Pediatric Scrotum Pediatric Imaging Clinical Perspective Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved FOCUS ON: Edward K. Sung 1 indu N. Setty Ilse Castro-ragon Sung EK, Setty N, Castro-ragon I Keywords: pediatrics, scrotum, trauma, tumor, ultrasound DOI:10.2214/JR.11.8034 Received September 30, 2011; accepted after revision December 10, 2011. 1 ll authors: Department of Radiology, oston Medical Center, 820 Harrison ve, FGH ldg, Third Fl, oston, M 02118. ddress correspondence to E. K. Sung (Edward.Sung@bmc.org). JR 2012; 198:996 1003 0361 803X/12/1985 996 merican Roentgen Ray Society Sonography of the Pediatric Scrotum: Emphasis on the Ts Torsion, Trauma, and Tumors OJECTIVE. The purpose of this article is to review the different scrotal disease entities in the pediatric population, focusing on acute scrotum, traumatic injuries, and testicular tumors. CONCLUSION. Many pediatric scrotal disorders can be well characterized on sonography. n understanding of the various disease entities, their clinical presentations, and the typical sonographic features should all be combined to make an accurate diagnosis. S onography is the imaging modality of choice for the evaluation of scrotal disorders in children. When combined with color Doppler, many scrotal diseases can be well characterized, guiding the clinician toward appropriate therapy. Common categories of scrotal diseases in the pediatric population include acute scrotum, traumatic injury, and tumors. cute Scrotum cute scrotum is defined as acute scrotal swelling and pain and is a common cause of presentation to the emergency department among boys. The common causes include testicular appendageal torsion, epididymitis, and testicular torsion [1]. Historical, clinical, and sonographic findings should all be used in making the diagnosis. Testicular Torsion Testicular torsion accounts for up to 26% of cases of acute scrotum [2] and is the most important diagnosis to rule out because it is a surgical emergency. ecause of the disruption of testicular blood supply in torsion, time is a crucial factor in salvaging the affected testis. The salvage rate can be up to 80 100% with surgery within 6 hours, and less than 20% with surgery after 12 hours [3]. Patients usually present with acute onset of diffuse scrotal pain, nausea, and vomiting. Physical findings can include high-riding testicle and absent cremasteric reflex. On sonography (Fig. 1), the torsed testicle may be enlarged and appear hypoechoic, but it can appear relatively normal in the first few hours. Other findings may include visualization of a torsed spermatic cord, scrotal edema, and reactive hydroceles. Color Doppler usually shows reduced or absent blood flow to the testicle, a highly specific finding [2 4]. False-negative Doppler evaluations can occur in the setting of partial torsion, spontaneous detorsion, or incorrect measurement of arterial waveforms along the periphery of the testicle. In these settings, repeat ultrasound should be considered, and attention should be made to the centripetal testicular arteries. False-positive Doppler evaluation can be seen in infants and young boys who often have normally reduced intratesticular blood flow [3], but this is currently less problematic with the availability of modern more-sensitive equipment. Moreover, comparison should always be made to the unaffected side for symmetry. Testicular ppendageal Torsion Testicular appendageal torsion is a common cause of acute scrotum in prepubertal boys [2, 5]. The appendages are normal remnants of embryonic tissue and are usually located at the superior testicle or epididymal head. Testicular appendages are more prevalent than epididymal appendages [5]; however, the distinction is often difficult to make and is not important clinically. Patients typically present with focal scrotal pain of variable onset. Physical findings can include a paratesticular nodule and bluish skin discoloration on the scrotum (i.e., the blue dot sign) [5, 6]. Sonography may show an oval avascular mass (torsed appendage) with variable echogenicity located between the testicle and 996 JR:198, May 2012

Ultrasound of Pediatric Scrotum Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved epididymis (Fig. 2). dditional findings may include scrotal edema and reactive hydroceles. Color Doppler may show hyperemia surrounding the torsed appendage [5, 6]. Treatment involves conservative management. Epididymitis Epididymitis is another common cause of acute scrotum, accounting for up to 21% of cases [2]. In postpubertal male patients, it is usually related to retrograde extension of infection. In prepubertal boys, it is mostly idiopathic but can be related to underlying urogenital anomalies [7]. Patients typically present with gradual onset of scrotal pain with fevers. Sonography may show an enlarged hypoechoic epididymis, scrotal edema, and reactive hydroceles (Fig. 3). Color Doppler will show hyperemia around the epididymis [2, 7, 8]. Concurrent orchitis can occur in 20 40% of cases [8]. Treatment commonly involves antibiotics. Other Causes of Scrotal Swelling cute idiopathic scrotal edema is a rare disease that can cause acute scrotal swelling and erythema in boys [9] and is usually painless. Its exact cause is unclear, but it may have an allergic origin. Sonography and color Doppler show diffuse scrotal edema and hyperemia [9] (Fig. 4). cute idiopathic scrotal edema is self-limited, and treatment is conservative. nother cause of acute scrotal pain and swelling in the pediatric population is Henoch-Schönlein purpura. Henoch-Schönlein purpura is a systemic vasculitis more commonly seen in children that usually affects the skin, kidneys, gastrointestinal tract, and joints. Scrotal involvement is rare but can occur in up to 15% of cases, and the sonographic findings typically include thickening of the scrotal skin, enlargement of the epididymis, and presence of a hydrocele [10]. In Henoch-Schönlein purpura, the testes are usually unaffected, and normal testicular blood flow is maintained. In general, the presence of scrotal swelling in boys should also raise the possibility of cellulitis or skin reaction from insect bites. In this setting, the major causes of scrotal swelling should initially be ruled out, and careful history and physical examination may guide the clinician into the appropriate diagnosis. Trauma Traumatic testicular injuries are relatively uncommon because the testes are protected by mobility within the scrotum, laxity of the overlying skin, and coverage by the tunica albuginea [11, 12]. Scrotal trauma in boys is most commonly due to sports-related activity (> 50%) followed by motor vehicle accidents (17%) [11]. Testicular Rupture Testicular rupture involves disruption of the tunica albuginea, with extrusion of testicular contents. This can lead to loss of the normal oval shape of the testicle. Sonography shows a heterogeneous testicle with irregular contours and a disrupted tunica albuginea [11, 12] (Figs. 5 and 6). Treatment involves urgent surgical repair [11]. Testicular Fracture Testicular fracture involves a break or discontinuity within the normal testicular parenchyma. However, the tunica albuginea remains intact, and thus the testicle maintains its normal shape. Sonography shows a linear hypoechoic fracture line within the normally shaped testicle [11, 12] (Fig. 7). Treatment is usually conservative management. Testicular Hematoma Testicular hematomas may be intratesticular or extratesticular. Sonography usually shows an avascular heterogeneous region within or outside the testicle, corresponding to the hematoma [11, 12] (Figs. 5 and 7). Treatment of small hematomas is usually conservative; however, large hematomas may require surgical evacuation to prevent pressure necrosis and testicular atrophy [11]. Tumors Testicular tumors in boys are rare, accounting for only 1 2% of all pediatric solid neoplasms, with an incidence of only 0.5 2 per 100,000 boys [2, 13]. Most (> 95%) intratesticular lesions are malignant and typically present as a painless mass, with treatment usually involving orchiectomy. Testicular tumors are classified as germ cell tumors or non germ cell tumors. Germ cell tumors are further classified as seminomas and nonseminomatous tumors. Seminomas are the most common testicular tumors among men, whereas nonseminomatous germ cell tumors are the most common testicular tumors among boys and include yolk sac tumors, teratomas, embryonal carcinomas, and choriocarcinomas. Non germ cell tumors include Sertoli and Leydig cell tumors and are rare in boys [2, 13]. Yolk Sac Tumors Yolk sac tumors are the most common testicular tumors in boys, accounting for up to 80% of cases, with a peak incidence at age 2 years [2, 13, 14]. Serum α-fetoprotein levels are usually elevated. Sonography may reveal a heterogeneous solid mass replacing the entire testis (Fig. 8). Treatment involves radical orchiectomy, followed by routine monitoring of serum α-fetoprotein levels [13]. Teratoma Teratomas are the second most common testicular tumors among boys. Sonography will reveal a heterogeneous mass, usually with solid and cystic components (Fig. 9). Echogenic fat or calcifications may also be seen [2, 13, 14]. In prepubertal testes, teratomas are considered benign and can be treated with testis-sparing surgery. However, postpubertal teratomas are malignant and require orchiectomy [13]. Lymphoma and Leukemia Lymphoma and leukemia are the most common metastases to the testes. Lymphoma accounts for only 5% of all testicular tumors [14] but is the most common cause of bilateral testicular tumors. mong boys, the testes are also common sites of posttreatment leukemia recurrence [14]. Sonography may show a diffusely enlarged hypoechoic testicle or multifocal hypoechoic nodules [2, 14] (Fig. 10). Tumor Mimickers enign conditions can mimic the appearance of tumors. ccurate diagnoses of these disorders can prevent unnecessary orchiectomy. In some cases, history and physical examination findings are often equivocal, and the diagnosis may be dependent on the sonographic findings. These benign conditions may appear cystic or heterogeneous on sonography. enign cystic lesions include epidermoid, tunica albuginea, and intratesticular cysts. Epidermoid cysts have characteristic sonographic appearances, either as a rounded hypoechoic lesion with a hyperechoic rim, or the more classic lamellated onion ring appearance [15]. Tunica albuginea and intratesticular cysts appear as simple cystic lesions on sonography. lthough it can be difficult to distinguish the two, tunica albuginea cysts are usually located more peripherally along the tunica albuginea [15]. Heterogeneous-appearing benign lesions include adrenal rests and segmental testicular infarcts. drenal rests are caused by aberrant adrenal tissue trapped in the gonads during embryonic development. They can be JR:198, May 2012 997

Sung et al. Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved associated with congenital adrenal hyperplasia. Sonography may show a hypoechoic heterogeneous lesion that is eccentrically located and is frequently bilateral [14] (Fig. 11). Segmental testicular infarcts can be iatrogenic or related to predisposing conditions, such as polycythemia vera or sickle cell disease. Sonography typically shows an avascular wedge-shaped hypoechoic lesion, which can resolve over time [15] (Fig. 12). Testicular Microlithiasis Testicular microlithiasis is due to calcium deposition within seminiferous tubules. It can be associated with conditions such as cryptorchidism and Klinefelter syndrome. Ultrasonographic criteria include visualization of at least five microliths on a single image [2, 8, 14, 16] and may be unilateral or bilateral and focal or diffuse (Figs. 13 and 14). The predisposition of testicular microlithiasis for malignancy is still unclear, and follow-up in asymptomatic patients may involve self-examinations; however, ultrasound should be considered in symptomatic patients, patients with a history of malignancy, or on patient request [16]. Conclusion Many scrotal and testicular diseases can affect the pediatric population, ranging from acute disorders such as testicular torsion and traumatic injuries to other less common disorders such as malignancies. The initial imaging modality of choice is sonography. Thorough knowledge of the typical clinical and sonographic findings of these disorders is necessary in making accurate diagnoses to guide appropriate therapy. References 1. aldisserotto M. Scrotal emergencies. Pediatr Radiol 2009; 39:516 521 2. so C, Enriquez G, Fite M, et al. Gray-scale and color Doppler sonography of scrotal disorders in children: an update. RadioGraphics 2005; 25: 1197 1214 3. Prando D. Torsion of the spermatic cord: the main gray-scale and Doppler sonographic signs. bdom Imaging 2009; 34:648 661 4. Chmelnik M, Schenk JP, Hinz U, Holland-Cunz S, Gunther P. Testicular torsion: sonomorphological appearance as a predictor for testicular viability and outcome in neonates and children. Pediatr Surg Int 2010; 26:281 286 5. aldisserotto M, Ketzer de Souza JC, Pertence P, Dora MD. Color Doppler sonography of normal and torsed testicular appendages in children. JR 2005; 184:1287 1292 6. Singh K, Kao SC. Torsion of testicular appendage. Pediatr Radiol 2010; 40:373 7. Karmazyn, Kaefer M, Kauffman S, Jennings SG. Ultrasonography and clinical findings in children with epididymitis, with and without associated lower urinary tract abnormalities. Pediatr Radiol 2009; 39:1054 1058 8. Kim W, Rosen M, Langer JE, anner MP, Siegelman ES, Ramchandani P. US-MR imaging correlation in pathologic conditions of the scrotum. RadioGraphics 2007; 27:1239 1253 9. Lee, Park SJ, Lee HK, Hong HS, Lee H, Kim DH. cute idiopathic scrotal edema: ultrasonographic findings at an emergency unit. Eur Radiol 2009; 19:2075 2080 10. en-sira L, Laor T. Severe scrotal pain in boys with Henoch-Schönlein purpura: incidence and sonography. Pediatr Radiol 2000; 30:125 128 11. hatt S, Dogra VS. Role of US in testicular and scrotal trauma. RadioGraphics 2008; 28:1617 1629 12. Deurdulian C, Mittelstaedt C, Chong WK, Fielding JR. US of acute scrotal trauma: optimal technique, imaging findings, and management. RadioGraphics 2007; 27:357 369 13. garwal PK, Palmer JS. Testicular and paratesticular neoplasms in prepubertal males. J Urol 2006; 176:875 881 14. Woodward PJ, Sohaey R, O Donoghue MJ, Green DE. Tumors and tumorlike lesions of the testis: radiologic-pathologic correlation. RadioGraphics 2002; 22:189 216 15. Dogra VS, Gottlieb RH, Rubens DJ, Liao L. enign intratesticular cystic lesions: US features. RadioGraphics 2001; 21:S273 S281 16. Chiang LW, Yap TL, siri MM, Ong CCP, Low Y, Jacobsen S. Implications of incidental finding of testicular microlithiasis in paediatric patients. J Pediatr Urol 2011 [Epub ahead of print] Fig. 1 12-year-old boy with left-sided testicular torsion., Color Doppler ultrasound image shows severely diminished blood flow to left testicle (asterisk). Note soft-tissue mass (arrow) next to left testicle, corresponding to torsed spermatic cord., Color Doppler ultrasound image adjacent to torsed testicle shows twisted appearance of spermatic cord (arrows), consistent with torsion of spermatic cord. Minimal color flow is seen centrally within spermatic cord, uncommon finding. lso note associated reactive hydrocele (asterisk). (Fig. 1 continues on next page) 998 JR:198, May 2012

Ultrasound of Pediatric Scrotum Fig. 1 (continued) 12-year-old boy with left-sided testicular torsion. C, Color Doppler ultrasound image obtained after surgical detorsion shows reperfusion (asterisk) of previously torsed left testicle. Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved C Fig. 2 3-year-old boy with appendageal torsion., Gray-scale ultrasound image shows well-defined oval-shaped mass (asterisk) next to epididymis (arrow) and testicle (T), consistent with torsed appendage. It is often difficult to distinguish between testicular and epididymal appendages; however, testicular appendages are more common., Color Doppler ultrasound image shows hyperemia (asterisk) around torsed appendage. Note central salt-and-pepper pattern from edema of torsed appendage, common finding. Fig. 3 4-month-old boy with epididymoorchitis., Gray-scale ultrasound image shows diffusely enlarged heterogeneous epididymis (arrows), consistent with epididymitis. Gray-scale ultrasound appearance of testicle (asterisk), however, is normal., Color Doppler ultrasound image shows hyperemia around epididymis (arrows) and testicle (asterisk), consistent with inflammation in epididymoorchitis. JR:198, May 2012 999

Sung et al. Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved Fig. 4 11-year-old boy with acute onset of painless scrotal swelling, consistent with acute idiopathic scrotal edema., Gray-scale ultrasound image shows diffuse scrotal edema (asterisks). Note normal appearance of testes., Color Doppler ultrasound image shows increased vascularity in edematous scrotum (arrows). Note normal vascularity of testes. Fig. 5 18-year-old man with testicular rupture after blunt trauma. Gray-scale ultrasound image shows interruption of echogenic tunica albuginea (arrow). djacent heterogeneously echogenic material (asterisk) likely represents extruded testicular material as well as associated extratesticular hematoma. Fig. 6 13-year-old boy with testicular rupture after penetrating trauma from gunshot injury. Gray-scale ultrasound image shows abnormal contour of testicle, as well as linear hyperechoic region (arrows), representing air along bullet tract. This should not be confused with testicular microlithiasis (see Figs. 13 and 14). Fig. 7 17-year-old boy with testicular fracture after blunt trauma., Gray-scale ultrasound image shows linear hypoechoic fracture line (arrows). lso note heterogeneous region (asterisk), consistent with intratesticular hematoma. (Fig. 7 continues on next page) 1000 JR:198, May 2012

Ultrasound of Pediatric Scrotum Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved Fig. 7 (continued) 17-year-old boy with testicular fracture after blunt trauma., nother gray-scale ultrasound image of affected testicle shows large heterogeneous mostly hyperechoic region (asterisk), compatible with intratesticular hematoma. C, Color Doppler ultrasound image shows lack of vascularity within center of abnormal heterogeneous region (asterisk), compatible with intratesticular hematoma. Fig. 8 2-year-old boy with yolk sac tumor., Gray-scale ultrasound image shows large slightly hyperechoic mass (margins outlined by arrows) almost replacing entire testis., Color Doppler ultrasound image shows diffusely increased vascularity around tumor. (Courtesy of Chow J, Children s Hospital, oston, M) C Fig. 9 6-month-old boy who presented with left testicular swelling. Gray-scale ultrasound image shows heterogeneous mass replacing entire testicle, with solid and cystic components, most compatible with teratoma, which was confirmed on pathologic analysis. JR:198, May 2012 1001

Sung et al. Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved Fig. 10 5-year-old boy with testicular lymphoma., Gray-scale ultrasound image shows diffuse heterogeneous echotexture of testicle, which is enlarged. No discrete mass is identified., Color Doppler ultrasound image shows increased vascularity, more compatible with malignant process. Fig. 11 15-year-old boy with congenital adrenal hyperplasia, found to have testicular adrenal rest., Gray-scale ultrasound image shows lobular heterogeneous intratesticular mass (arrow)., Color Doppler ultrasound image shows diffusely increased vascularity (arrow) within and around mass. Fig. 12 18-year-old man with sickle cell disease and testicular pain found to have segmental testicular infarct., Color Doppler ultrasound image shows wedge-shaped hypoechoic region (asterisk) without vascularity, consistent with focal infarct., Two-week follow-up color Doppler ultrasound image shows nearly complete resolution of infarct (asterisk) and return of normal vascularity. 1002 JR:198, May 2012

Ultrasound of Pediatric Scrotum Downloaded from www.ajronline.org by 37.44.201.148 on 01/21/18 from IP address 37.44.201.148. Copyright RRS. For personal use only; all rights reserved Fig. 13 17-year-old boy with diffuse testicular microlithiasis. Gray-scale ultrasound image shows innumerable echogenic foci (i.e., microliths) spread diffusely throughout both testicles. FOR YOUR INFORMTION Fig. 14 13-year-old boy with focal testicular microlithiasis. Gray-scale ultrasound image shows several punctate echogenic foci (arrows), consistent with microliths. Unique customized medical search engine service from RRS! RRS GoldMiner is a keyword- and concept-driven search engine that provides instant access to radiologic images published in peer-reviewed journals. For more information, visit http://goldminer.arrs.org. JR:198, May 2012 1003