Nonobliteration of the Processus Vaginalis

Transcription

1 PICTORIAL ESSAY Nonobliteration of the Processus Vaginalis Sonography of Related Abnormalities in Children Vasileios Rafailidis, MD, MSc, Sotirios Varelas, MD, Foteini Apostolopoulou, MD, Dimitrios Rafailidis, MD, PhD The objective of this pictorial essay is to systematically classify processus vaginalis related disorders in the light of embryology and present illustrative sonograms with corresponding diagrams. Failure of the processus vaginalis to obliterate during gestation results in a wide spectrum of anomalies, including communicating and noncommunicating hydroceles and inguinal and inguinoscrotal hernias, along with other related disorders of the genital system. There are varying classifications in the literature regarding the aforementioned entities. Proper and timely diagnosis of these entities is essential, given the differences in treatment. Although physical examination can narrow the differential diagnosis, sonography plays an essential role in establishing the diagnosis. Key Words cryptorchidism; hernia; pediatric ultrasound; processus vaginalis; scrotal hydrocele; sonography Received April 21, 2015, from the Department of Radiology, AHEPA University General Hospital, Thessaloniki, Greece (V.R.); and Department of Radiology, G. Gennimatas General Hospital, Thessaloniki, Greece (S.V., F.A., D.R.). Revision requested June 19, Revised manuscript accepted for publication July 18, Address correspondence to Vasileios Rafailidis, MD, MSc, Department of Radiology, AHEPA University General Hospital, St Kiriakidis 1, Thessaloniki, Greece. billraf@hotmail.com doi: /ultra Hydroceles and hernias of the inguinal and scrotal areas represent an embryologic and clinical continuum of conditions that are quite common in pediatric clinical practice. A thorough understanding of the embryology of the processus vaginalis is essential in recognizing the various types of these congenital abnormalities. The wide spectrum of abnormalities caused by incomplete obliteration of the processus vaginalis includes communicating and noncommunicating hydroceles and inguinal and inguinoscrotal hernias. All of these disorders present with a painless bulge in the groin, scrotum, or both. A careful history and physical examination are necessary for the initial diagnostic evaluation; however, sonography plays a crucial role in the proper diagnosis and management. 1 Given the differences in the management of these abnormalities and the risk of complications in the absence of timely diagnosis and treatment, radiologists examining children with inguinal and scrotal swelling should be familiar with their sonographic findings. 1,2 The objective of this pictorial essay is to present the sonographic findings and illustrate a classification of the various types of hydroceles and hernias in children by the American Institute of Ultrasound in Medicine J Ultrasound Med 2016; 35:

2 Technical Considerations for Sonographic Examinations Linear array transducers, in range of 5 to 15 MHz, which are suitable for examinations of superficial structures, should be used. The high-frequency linear transducers are characterized by a high resolution in the examination field. Although the contact area of a linear transducer is relatively long, its field of view is restricted and often impedes evaluation of the full length of an abnormality and its surrounding anatomy. Due to the limited field of view of these transducers, long structures such as inguinoscrotal hernias and hydroceles are not easily depicted in a single view. This shortcoming is overcome by the use of technologies such as extended field-of-view imaging. When the latter is not available, serial images can be obtained and then juxtaposed to produce composite images showing the entire length of a lesion. 3 Embryology of the Processus Vaginalis The processus vaginalis represents an outpouching of the parietal peritoneum, which passes through the abdominal wall and extends caudally toward the scrotum in boys and the labium majora in girls. The processus vaginalis appears during the second and third months of gestation and is situated anteriorly to the developing testes and gubernaculum. 1,2 The gubernaculum is attached to the lower pole of the testis and assists its descent into its normal position inside the scrotum. 1 While the processus vaginalis is formed, it is covered by extensions of the layers of the abdominal wall, which ultimately contribute to the final formation of the scrotum. 2 During the seventh, eighth, and ninth months of gestation, certain hormonal stimuli cause the testes to descend from the abdominal cavity to the scrotum through the inguinal canal and along the processus vaginalis, which is pushed anteriorly, while the gubernaculum regresses (Figure 1). 1,2 The testis needs a few days to traverse the inguinal canal but 4 weeks to migrate from the external inguinal ring to the lower part of the scrotum. 1 Hormonal changes cause the processus vaginalis to obliterate only after testicular migration is complete. Normal obliteration is completed in 3 steps. The first step includes closure of the deep inguinal ring, and then the part of the processus vaginalis superior to the testis is obliterated. The remaining cavity between these obliterated parts is called the funicular process and is the last to obliterate, leading to atresia of the processus vaginalis. Once the process of obliteration is complete, the portion of the processus vaginalis covering the testis forms the tunica vaginalis. 2,4 The tunica vaginalis is the most inner mesothelium-lined layer covering the testis in the scrotum. It constitutes a double sac with a visceral layer covering the testis in contact with the tunica albuginea and a parietal layer lining the internal spermatic fascia of the scrotal wall. The testis is almost entirely covered by the tunica vaginalis, except for a small part in its posterior surface next to the mediastinum testis, where the vas deferens and testicular blood vessels can be found. 2 The above-described obliteration of the processus vaginalis is important, as when incomplete, it results in different types of congenital abnormalities. More precisely, a completely patent processus vaginalis is the cause of either a congenital communicating hydrocele or an indirect inguinoscrotal hernia. When the funicular process fails to obliterate proximally and communicates with the abdomen, a funicular hydrocele occurs. A funicular hydrocele can lead to formation of an inguinal hernia. When there is a proximally and distally obliterated funicular process with a patent central part, an encysted hydrocele arises. Complete obliteration of the proximal part of the processus vaginalis coexisting with a partially open processus vaginalis distally results in a noncommunicating hydrocele. A patent processus vaginalis may represent the underlying cause of an undescended testis or an ovary-containing hernia. If none of these abnormalities occur, a patent processus vaginalis may be undiagnosed or incidentally found on sonography. 2 The incidence of such congenital anomalies is generally inversely proportional to the child s age. 1,2,4,5 Figure 1. Processus vaginalis before obliteration. This diagrammatic representation shows the testis descending through the inguinal canal toward the scrotum. 806 J Ultrasound Med 2016; 35:

3 Approximately 20% of the population are born with a patent processus vaginalis and are usually asymptomatic. An open processus vaginalis normally closes during the first year of life. Situations causing delay or failure of closure of the processus vaginalis include premature birth, hip dysplasia, cystic fibrosis, Ehlers-Danlos syndrome, peritoneal dialysis, and ventriculoperitoneal shunts. 2 Sonographic Findings of Obliterated and Patent Processus Vaginales Sonography in asymptomatic children identifies the collapsed layers of a processus vaginalis as isoechoic or hyperechoic linear bands, which spread from the internal inguinal ring to the scrotum. These bands may be seen in contiguity with the tunica albuginea of the testis (Figure 2). A patent processus vaginalis can be sonographically visualized as a hydrocele caused by inflow of peritoneal fluid during straining of the child when crying or standing. When examining a child at rest or in the supine position, a Figure 2. Normally obliterated processus vaginalis. A, Diagram showing the normally obliterated processus vaginalis along with the normal anatomy of the contents of the spermatic cord. B, Split-screen sonogram where the screens were aligned to cover a longitudinal view of the inguinal area in a 2-year-old boy, showing a normally appearing spermatic cord from the deep inguinal ring (asterisk) to the scrotum. The collapsed layers of the processus vaginalis appear as isoechoic to hyperechoic lines (arrowhead). patent processus vaginalis may not be evident. 6,7 It can be visualized as a tubular hypoechoic structure, which originates from the internal inguinal ring and extends toward the scrotum. 7 When examining a patent processus vaginalis, applying pressure during both palpation and sonography can eliminate it (Figure 3). 1 When the processus vaginalis is only partially patent, a partially undescended or gliding testis can be present. The existence of septa inside the processus vaginalis may prevent the testis from reaching its normal position inside the scrotum (Figure 4). 2 Classification of Patent Processus Vaginalis Related Anomalies When reviewing the literature regarding hydroceles, one may encounter differences in the classification and nomenclature according to different authors. Based on a generalized classification, hydroceles can be divided into 2 categories depending on the patency of the proximal processus vaginalis and communication with the abdominal cavity: noncommunicating and communicating. Some authors consider hernias and hydroceles essentially the same entity. 5 When it comes to hydroceles situated in the spermatic cord, some authors divide them into 3 types: communicating, funicular, and encysted. 2 Others prefer to include only the latter 2 under the term spermatic cord hydroceles. 8 In Figure 5, we present a combination of the existing classification schemes including all types of hydroceles and inguinal hernias based on embryology. Figure 3. Serial longitudinal sonograms obtained and juxtaposed to produce a composite image showing the entire length of a patent processus vaginalis in a 2.5-year-old boy. A, The patent processus vaginalis is not seen in the supine position and at rest. There is fluid surrounding the testis (T) and in the peritoneal cavity (arrows) indicating the patency of the processus vaginalis. B, The patent processus vaginalis is detectable by the inflow of fluid into the processus vaginalis (arrow) when the boy is straining. J Ultrasound Med 2016; 35:

4 Types of Communicating Hydroceles The term communicating spermatic cord hydrocele refers to a fluid collection originating from the pelvis and extending to the scrotum through the deep inguinal ring. This type is virtually the same as a completely patent processus vaginalis. 2 According to different authors, a communicating hydrocele may not necessarily reach the scrotum but may end along the inguinal canal (Figure 6). 1 A funicular hydrocele results from failure of the processus vaginalis to obliterate at the level of the deep inguinal ring. There is also patency of the proximal funicular process, which extends toward the testis, where it is closed by a constriction. It resembles a peritoneal diverticulum and is usually found in premature neonates and children. Sonography reveals a fluid collection originating from the deep inguinal ring but not reaching the scrotum. In some cases, funicular hydroceles appear beaded, as a result of fibrous tissue and partial constrictions due to incomplete atresia of the funicular process or inflammatory processes. Due to the communication of funicular hydroceles with the peritoneal cavity, changes in the intra-abdominal pressure during straining or relaxing increase and decrease the hydrocele s volume, respectively. Because of the possibility that a funicular hydrocele can cause an indirect hernia, herniotomy is required (Figures 7 and 8). 2,4 Figure 4. Partially patent processus vaginalis in combination with cryptorchidism. A, Diagram showing an undescended testis located on the course of a patent processus vaginalis due to an obstacle such as an internal septum. B, Long-axis sonogram showing an undescended testis inside a partially patent processus vaginalis, into the inguinal canal, in a 40-day-old boy. Both proximal and distal parts of the processus vaginalis are obliterated. The testis, epididymis, and gubernaculum (arrowhead) can be seen inside the patent part of the processus vaginalis. C and D, Long-axis sonograms of the contralateral hemiscrotum of the same boy showing a gliding testis (T) sliding between the scrotum (C) and inguinal canal (D, arrow representing the movement) while the transducer was in the same position. 808 J Ultrasound Med 2016; 35:

5 An abdominoscrotal hydrocele is another type of hydrocele, which is very rare, as there are less than 100 reported pediatric cases, but it is also found in adults. It was first described by Guillaume Dupuytren in ,10 The first pediatric abdominoscrotal hydrocele was reported in This type refers to a large dumbbellshaped inguinoscrotal hydrocele, which protrudes into the peritoneal cavity through the internal inguinal ring. From a clinical point of view, an abdominoscrotal hydrocele is a communicating type of hydrocele. It is characteristically demonstrated by the positive cross-fluctuation test of the scrotal and abdominal swelling. During this clinical test, compression of the scrotal part of the abdominoscrotal hydrocele will cause enlargement of the abdominal part and vice versa. 11 The exact mechanism of this type of hydrocele is not yet clear. Sonography should identify an encapsulated anechoic fluid collection extending from the scrotum to the abdominal cavity. Multiplanar computed tomography or magnetic resonance imaging may be needed to evaluate the full extent of such a hydrocele. 3,10 Due to its large size and intra-abdominal extension, an abdominoscrotal hydrocele may cause complications such as hydroureteronephrosis, lower extremity edema, testicular dismorphism, interruptions of spermatogenesis, and appendicitis. Surgical repair should be performed in children with abdominoscrotal hydroceles except for cases with a high surgical risk, in which periodic physical examinations and sonographic follow-up are chosen (Figure 9). 9,11 Figure 5. Classification of processus vaginalis (PV) related disorders. Figure 6. Communicating hydrocele. A, Diagram showing the existence of a communicating hydrocele extending from the open deep inguinal ring to the scrotum. B, Series of 4 longitudinal sonograms juxtaposed to produce a composite image showing the entire length of a communicating hydrocele in a 10-year-old-boy. The testis (T) can be seen located at the distal end of the hydrocele. J Ultrasound Med 2016; 35:

6 Figure 7. Funicular hydrocele. A, Diagram showing a funicular hydrocele of the spermatic cord, which communicates with the peritoneal cavity and resembles a diverticulum. Sometimes, the proximal part of a funicular hydrocele may appear beaded due to remnants of partial constrictions. B, Split-screen composite image showing a funicular hydrocele in a 10-month-old infant. There is an ovoid fluid collection extending from the patent deep inguinal ring (asterisk) to the ipsilateral testis (T), which is located outside the hydrocele and inside the scrotum. C, Splitscreen composite image showing a funicular hydrocele with 2 internal septa (arrows) in a 45-day-old boy. When it comes to female children, failure of the processus vaginalis to obliterate results in formation of the canal of Nuck. Hydrocele of the canal of Nuck refers to the presence of a fluid collection inside the respective canal and is a rare entity, with almost 400 reported cases. This type of hydrocele may present as a labial mass and has various sonographic appearances. It can be described as a dumbbell-shaped cyst, a tubular cyst, or a comma-shaped cyst with or without internal septa. Treatment options include drainage, surgical excision, and laparoscopic closure. 12,13 Figure 8. Funicular hydrocele of the spermatic cord in combination with scrotal fluid. A, Diagrammatic representation showing the presence of fluid in a proximally patent processus vaginalis and within scrotum. B, Split-screen composite sonogram showing both funicular and scrotal hydrocele in a 50-day-old boy. The funicular hydrocele (arrow) communicates with the peritoneal cavity through the widely open deep inguinal ring. Note the presence of the ipsilateral testis (T) and epididymis (arrowhead). 810 J Ultrasound Med 2016; 35:

7 Types of Noncommunicating Hydroceles The term scrotal hydrocele refers to the presence of a fluid collection inside the tunica vaginalis. This collection is limited to inside the scrotum and surrounds the testis. 1 It should be noted that 1 to 2 ml of serous fluid may normally be found in the potential cavity created by the tunica vaginalis. This small quantity of fluid does not constitute a hydrocele. 3 In this type of hydrocele, the processus vaginalis is normally obliterated from the internal inguinal ring to the upper extent of the tunica vaginalis. As a result, a scrotal hydrocele does not communicate with the peritoneal cavity through the inguinal canal and can be thus categorized as noncommunicating (Figures 10 and 11). 1,5 Apart from the congenital type, a scrotal hydrocele may also be caused after birth by an inflammatory or infectious process or scrotal trauma. These types are more frequently seen in older children. 1,3 The term encysted hydrocele describes a fluid collection that is enclosed between proximal and distal constrictions anywhere along the spermatic cord and does not communicate with the peritoneal cavity. An encysted hydrocele may vary in shape and size over weeks and clinically resemble the testis. It varies in shape and size but is not affected by changes in the intra-abdominal pressure. Sonography is very sensitive and accurate in diagnosing an encysted hydrocele and identifies a usually ovoid or round avascular mass somewhere along the spermatic cord whose echogenicity depends on its contents. Clear fluid collections appear anechoic or hypoechoic (Figure 12). Encysted hydroceles containing cholesterol deposits may Figure 9. Abdominoscrotal hydrocele. A, Diagram showing a dumbbell-shaped abdominoscrotal hydrocele. B, Four serial longitudinal sonograms obtained and juxtaposed to produce a composite image showing the entire length of an approximately 13-cm-long hydrocele in a 4-month-old boy. Note the extension of the hydrocele into the peritoneal cavity (curved arrow) and toward the scrotum (arrow). The testis (T) is shown below the deep inguinal ring (asterisk) and is impeded from reaching its normal position inside the scrotum (arrowhead indicates lateral abdominal muscles). Figure 10. Scrotal hydrocele. A, Diagrammatic representation of a scrotal hydrocele. The processus vaginalis is completely obliterated in the inguinal area. There is a fluid collection limited to inside the scrotum. B, Longitudinal sonogram showing a congenital scrotal hydrocele in a 45-day-old boy. J Ultrasound Med 2016; 35:

8 Figure 11. Bilateral congenital scrotal hydrocele in a 40-day-old neonate. A, Long-axis sonogram showing a large fluid collection in the right hemiscrotum along with the obliterated processus vaginalis. The spermatic cord measures 2.8 mm in width (cursors). B, Transverse sonogram of the scrotum showing the presence of a severe bilateral scrotal hydrocele. C, Long-axis sonogram showing a large fluid collection in the left hemiscrotum along with the obliterated processus vaginalis. The spermatic cord measures 4 mm in width (cursors). Figure 12. Encysted hydrocele. A, Diagrammatic representation of an encysted hydrocele. There is partial patency of the processus vaginalis in combination with proximal and distal closure. B, Long-axis sonogram showing an encysted hydrocele in a 6-year-old boy. The hydrocele is ovoid, shows increased through-transmission, and measures mm. The processus vaginalis is collapsed at its proximal and distal ends (arrows), and the hydrocele is limited to inside the patent funicular process. There is no associated scrotal hydrocele. C, Split-screen composite sonogram showing an ellipsoid encysted hydrocele (asterisk) in a 10-year-old boy. The hydrocele is shown touching and displacing the testis (T) downward but not surrounding it. 812 J Ultrasound Med 2016; 35:

9 be isoechoic. Protein aggregations may create low-level swirling echoes inside the hydrocele s fluid. These echoes should not be mistaken for a hematocele or pyocele. 14 Strong through-transmission is another characteristic sonographic finding of an encysted hydrocele, while the testis and epididymis may be displaced inferiorly. 2 4,8 Internal septa can also be found inside an encysted hydrocele in some children. 8 In some cases, sonography may reveal the coexistence of encysted and scrotal hydroceles (Figure 13). Differential diagnosis between an encysted and a funicular hydrocele may be done with sonography and relies on 2 important findings. First, the loculated nature of the fluid collection is characteristic of the encysted type. Second, we should always evaluate the deep inguinal ring, which is patent in funicular hydroceles and obliterated in encysted hydroceles. Due to its round shape, an encysted hydrocele may resemble a mass and needs differentiation from lymph nodes or other masses (including a paraepididymal cyst or abscess). 8 The female homologue of an encysted hydrocele is a cyst of the canal of Nuck, which results from complete proximal obliteration in combination with a patent distal portion of the processus vaginalis. 15 Hydroceles of all types can be found in approximately 14% of boys who are sonographically examined. 3 The encysted and funicular types of hydroceles are rarer and found in 0.77% of sonographic examinations. 8 Abdominoscrotal hydroceles represent the rarest, accounting for only 0.17% of all types of hydroceles. 10 Inguinal and Inguinoscrotal Hernias An incompletely obliterated processus vaginalis increases the danger of an inguinal or inguinoscrotal hernia. In these cases, part of the omentum, intestinal loops, or other intraabdominal organs such as the ovary and fallopian tube enter the processus vaginalis. 2 In other words, it is the protrusion of an intra-abdominal organ into the open processus vaginalis that defines the presence of an inguinal hernia. This type of inguinal hernia is called indirect, as it traverses the inguinal canal and in most cases is congenital. 1,3,16 Congenital inguinal hernias affect boys more frequently, are more commonly located on the right side, and occur with an incidence at birth of 0.88% to 4.4%. However, up to 11% of premature neonates may be affected. 17 Figure 13. Combination of encysted and scrotal hydroceles. A, Diagram showing the presence of both encysted and scrotal hydroceles. B, Three long-axis sonograms in a series revealing the presence of both encysted and scrotal hydroceles in a 2-month-old infant. The encysted hydrocele located in the spermatic cord displaces the testis and epididymis inferiorly. The latter are surrounded by fluid (arrow). C, Series of sonograms showing encysted and scrotal hydroceles in a 50-day-old boy. The proximal part of the processus vaginalis is obliterated. There is increased through-transmission behind both the encysted and scrotal hydrocele. Note the presence of a septum (arrowhead) inside the encysted hydrocele. D, Split-screen composite sonogram showing a small spheroid encysted hydrocele (asterisk) measuring 19 mm in a 40-day-old infant. Note the ipsilateral scrotal hydrocele (arrow) and the distally closed processus vaginalis (arrowheads). J Ultrasound Med 2016; 35:

10 Inguinoscrotal hernias usually occur in preterm neonates. Physical examination can establish the diagnosis. 2 The right-side predilection of the inguinal hernia and hydrocele may be explained by the later migration of the right testis compared to the left and the later closure of the right processus vaginalis. 3,5 A left inguinal hernia is more likely to coexist with a contralateral one. Bilateral hernias are present in approximately 16% of cases. This high frequency of bilaterality explains the need for bilateral physical examination in children with unilateral involvement. 1,5 An inguinal hernia may be asymptomatic and remain undiagnosed for years or may present with painful intermittent inguinal, scrotal, or labial bulges. The symptoms typically worsen when the child cries or strains due to the increased intra-abdominal pressure. Complications of inguinal and inguinoscrotal hernias include incarceration and strangulation with bowel obstruction. 5 Differential diagnosis between all of the aforementioned entities, including an inguinal hernia, an inguinoscrotal hernia, a communicating hydrocele, and noncommunicating types of hydroceles (encysted and scrotal) is crucial because communicating and noncommunicating hydroceles are treated differently. Physical examination can help and show evidence of the right diagnosis. All of these conditions present with a palpable inguinal mass. Nevertheless, some bulges may be present only when the intra-abdominal pressure increases, for example, during crying, or when the child is erect. It is possible that some bulges are smaller when the child is supine or during sleep. This intermittent nature of the bulge is characteristic of conditions that are communicating with the peritoneal cavity such as an inguinal hernia or a communicating type of hydrocele (communicating or funicular) and virtually excludes the presence of an encysted hydrocele. 1 Sonographic Findings of Hernias Children with inguinoscrotal masses should be evaluated with sonography to achieve an accurate diagnosis and proper surgical planning. 1,5 Regarding the diagnostic accuracy of sonography in the diagnosis of inguinal hernias, a recently published meta-analysis showed that it is 96.6% sensitive and 84.8% specific. 18 Although it was a metaanalysis of studies performed in adult patients, it is indicative of the value of this modality in the pediatric population as well. Sonography is needed to differentiate the diagnosis and to evaluate the contralateral inguinal canal. It has been reported that an inguinal ring wider than 4 mm is an indication for prophylactic herniorrhaphy. 3,5 Omentum is sonographically detected as echogenic material inside the hernia (Figures 14 and 15). Herniated intestinal loops are imaged as tubular structures, which contain hyperechoic air bubbles or fluid and show peristaltic waves (Figure 16). When examining a hernia, applying pressure during both palpation and sonography can reduce the hernia s contents. 1 Color or power Doppler techniques are necessary to identify the bowel s normal vascularity and to exclude ischemia due to strangulation (Figure 17). Branching omental vessels are also easily identified with Doppler techniques. 2,3 Prenatal diagnosis of an inguinoscrotal hernia Figure 14. Inguinal hernia. A, Diagram representing an inguinal hernia. B and C, Split-screen composite sonograms of the inguinal region of a 6.5- year-old boy with a inguinal hernia. The hernia sac is partially filled with fluid (B, arrowhead) and omentum (B, asterisk). The Valsalva maneuver in the same patient accentuates the visualization of this hernia by causing downwards extension of the content (C). 814 J Ultrasound Med 2016; 35:

11 is possible with sonography. Bowel peristalsis is a very characteristic imaging finding, indicating the diagnosis even in this setting. 17 In boys with inguinoscrotal hernias, intestinal loops can be found inside the scrotum (Figure 18). The term incarcerated inguinal hernia refers to the presence of an inguinal hernia that cannot be reduced spontaneously and is associated with a more severe clinical presentation. An inguinal hernia is incarcerated along with its contents, which can include the small and large intestine, appendix, omentum, ovary, fallopian tube, or a Meckel diverticulum. The frequency of hernia incarceration decreases with age but never completely disappears. Once a hernia is incarcerated, there is a high risk of strangulation, which should be urgently treated. Strangulation of a hernia refers to the loss of the blood supply in the herniated contents, which may result in bowel obstruction (Figure 17). 1,5,16 Six percent to 18% of patients and 30% of neonates younger than 2 months who present with an inguinal hernia will be affected by incarceration. This factor is the reason why hernias should be repaired promptly while the child is young. Figure 16. Sonography of an inguinal hernia before and after manual reduction in a 21-month-old boy. A, Sonogram showing an intestinal loop protruding through an open internal inguinal ring (arrow). The herniated loop s wall appears normal in width. B, Power Doppler image showing normal blood flow signals throughout the herniated loop s wall. C, Follow-up image the next day after manual reduction confirming the successful reduction of the herniated bowel inside the peritoneal cavity. The hernia sac contains only fluid. Figure 15. A C, Extended field-of-view sonograms from a 2-year-old boy with an inguinal hernia. This series of images shows progressive peripheral displacement of a hernia s content after straining. J Ultrasound Med 2016; 35:

12 3504jum copy_layout 1 3/25/16 7:48 AM Page 816 Regarding ovary-containing hernias, they are usually found in children younger than 5 years but are rarely found in infants. They should be promptly diagnosed because of the risk of torsion of the herniated ovary, which can also be associated with salpingitis and infertility.13,19 This type of hernia results from displacement of an ovary, the fallopian tube, the broad ligament, and possibly part of the uterus into the inguinal canal due to incomplete obliteration of Figure 17. Power Doppler sonography showing a strangulated inguinal hernia in a 40-day-old boy. A, Transverse sonogram of a non clinically reducible inguinal hernia. B, Longitudinal sonogram of the hernia. Bowel loops (B) can be seen extending through the internal inguinal ring (arrow). The power Doppler technique reveals blood flow signals in the hernia s neck but not in the herniated intestinal loops. Surgery confirmed the presence of a strangulated but still viable intestinal loop inside the hernia. Figure 18. Inguinoscrotal hernia. A, Diagram showing the passage of intestinal loops into the scrotal cavity. B and C, Sonograms from a 30day-old neonate with a bilateral inguinoscrotal hernia. The long-axis sonogram in B shows herniated intestinal loops extending toward the scrotum, where a fluid collection can be seen. Note the hyperechoic air bubbles (arrow) inside the loop. The sonogram of the contralateral inguinal canal of the same patient in C shows herniated intestinal loops inside the scrotum superior to the testis (T). 816 J Ultrasound Med 2016; 35:

13 the processus vaginalis. Sonography is useful in diagnosing this type of hernia by visualizing a mass with an ovarian or uterine echo structure and normal vasculature but without any peristalsis. A Doppler technique should always be used to determine the presence of blood flow within the ovary, as ischemic strangulated ovaries require emergency surgery (Figures 19 and 20). Strangulated ovaries appear engorged, avascular, and less mobile and compressible. 13 Surgery is the treatment of choice, aiming to place the ovaries inside the pelvis. 19 Apart from the entities presented in this pictorial essay, the sonographic differential diagnosis of inguinoscrotal swelling in children also includes torsion of the testis or a testicular appendage, epididymitis, hematoceles, vasitis, inguinal lymphadenitis, and rare testicular tumors. 1 Treatment Both communicating and noncommunicating hydroceles may resolve spontaneously in infants. Thus, they can be observed during the first year of life and then be treated with surgery if still present. Regarding hydroceles of the spermatic cord (encysted), they do not always resolve spontaneously but do not constitute a surgical emergency. It is suggested that they should be treated after the first year of life. 1 Different authors suggest that noncommunicating hydroceles may be observed for the first 2 years of life. 5 The same authors suggest that communicating hydroceles should be treated like hernias with surgery once the diagnosis has been made. An inguinal hernia should be treated with surgery once it is diagnosed because of the risk of complications such as incarceration and strangulation. 5 Figure 19. Sonography of an ovary-containing hernia in a 29-day-old female neonate. A, B-mode sonogram showing a mixed-echogenicity mass herniated through the internal inguinal ring. The mass has anechoic parts, which are consistent with the cystic follicles (arrows) of an ovary. B, Color Doppler image of the same patient revealing the presence of blood vessels in the hernia s neck (arrow). Surgery confirmed the presence of a herniated ovary. Figure 20. Sonography of a hernia containing an ovary and fallopian tube in a 4-month-old girl. A, B-mode sonogram showing 2 discrete echogenic masses (arrows) protruding through the internal inguinal ring into the hernia sac. Anechoic parts can be seen and are consistent with ovarian follicles (arrowhead). B, Color Doppler image revealing the presence of blood vessels oriented toward the masses. The possibility of strangulation was thus excluded. Surgery confirmed the presence of a viable herniated ovary and fallopian tube. J Ultrasound Med 2016; 35:

14 Conclusions Defective obliteration of the processus vaginalis results in a series of congenital abnormalities. Once an intraabdominal organ enters the patent processus vaginalis, the term hernia should be used to describe this entity. Since different types of hydroceles and hernias require different therapeutic approaches, and given the risk of various complications such as incarceration and strangulation, the related embryology, anatomy, and sonographic appearance of these entities should be familiar to anyone involved with the diagnostic dilemma of children with inguinoscrotal swelling. References 1. Palmer LS. Hernias and hydroceles. Pediatr Rev 2013; 34: Garriga V, Serrano A, Marin A, Medrano S, Roson N, Pruna X. US of the tunica vaginalis testis: anatomic relationships and pathologic conditions. Radiographics 2009; 29: Aso C, Enriquez G, Fité M, et al. Gray-scale and color Doppler sonography of scrotal disorders in children: an update. Radiographics 2005; 25: Martin LC, Share JC, Peters C, Atala A. Hydrocele of the spermatic cord: embryology and ultrasonographic appearance. Pediatr Radiol 1996; 26: Lao OB, Fitzgibbons RJ Jr, Cusick RA. Pediatric inguinal hernias, hydroceles, and undescended testicles. Surg Clin North Am 2012; 92: , vii. 6. Hata S, Takahashi Y, Nakamura T, Suzuki R, Kitada M, Shimano T. Preoperative sonographic evaluation is a useful method of detecting contralateral patent processus vaginalis in pediatric patients with unilateral inguinal hernia. J Pediatr Surg 2004; 39: Koutsoumis G, Patoulias I, Kaselas C. Primary new-onset hydroceles presenting in late childhood and pre-adolescent patients resemble the adult type hydrocele pathology. J Pediatr Surg 2014; 49: Rathaus V, Konen O, Shapiro M, Lazar L, Grunebaum M, Werner M. Ultrasound features of spermatic cord hydrocele in children. Br J Radiol 2001; 74: Yarram SG, Dipietro MA, Graziano K, Mychaliska GB, Strouse PJ. Bilateral giant abdominoscrotal hydroceles complicated by appendicitis. Pediatr Radiol 2005; 35: Jain S, Singh R, Singh SK, Singh V, Shantanu K. Abdominoscrotal hydrocele with intestinal malrotation: a rare association. Case Rep Radiol 2012; 2012: Blevrakis E, Anyfantakis DI, Sakellaris G. Abdominoscrotal hydrocele in a 9-month old infant. Hernia 2011; 15: Khanna PC, Ponsky T, Zagol B, Lukish JR, Markle BM. Sonographic appearance of canal of Nuck hydrocele. Pediatr Radiol 2007; 37: Patel B, Zivin S, Panchal N, Wilbur A, Bresler M. Sonography of female genital hernias presenting as labia majora masses. J Ultrasound Med 2014; 33: Collings C, Cronan JJ, Grusmark J. Diffuse echoes within a simple hydrocele: an imaging caveat. J Ultrasound Med 1994; 13: Ozel A, Kirdar O, Halefoglu AM, et al. Cysts of the canal of Nuck: ultrasound and magnetic resonance imaging findings. J Ultrasound 2009; 12: Inguinal hernias and hydroceles in infancy and childhood: a consensus statement of the Canadian Association of Paediatric Surgeons. Paediatr Child Health 2000; 5: Khatib N, Goldstein I, Vitner D, Ganem N, Livoff A, Wiener Z. Prenatal diagnosis of scrotal-inguinal hernia: two case reports and review of the English literature. Eur J Obstet Gynecol Reprod Biol 2013; 171: Robinson A, Light D, Nice C. Meta-analysis of sonography in the diagnosis of inguinal hernias. J Ultrasound Med 2013; 32: Bhosale PR, Patnana M, Viswanathan C, Szklaruk J. The inguinal canal: anatomy and imaging features of common and uncommon masses. Radiographics 2008; 28: J Ultrasound Med 2016; 35: