The challenging sonographic inguinal canal evaluation in neonates and children: an update of differential diagnoses

Encysted spermatic cord hydrocele: A case series

INTRODUCTION AND IMPORTANCE

Encysted spermatic cord hydrocele is a rare anomaly characterized by obstruction of processus vaginalis closure. Clinically, it presents as a swelling in the inguinal region extending to the upper scrotum and does not communicate with the peritoneal cavity. It is often mistaken for indirect inguinal hernias, inguinal lymphadenopathy, undescended testis, and primary tumors of the cord in infants and children, making the diagnosis challenging.

CASE PRESENTATION

We report the cases of five male patients aged nine months to 12 years who presented with painless swelling on the right side of the scrotal region. Physical examination revealed firm masses in the right inguinal region with positive transillumination, negative cough impulse tests, and irreducibility. Inguinal and scrotal ultrasonography showed an anechoic cystic lesion with thin walls, without any signs suggestive of a hernia. Patients were diagnosed with encysted spermatic cord hydrocele and advised to undergo cyst excision. The postoperative periods were uneventful, and expected recovery was observed at one-week and one-month follow-ups.

CLINICAL DISCUSSION

Encysted spermatic cord hydroceles are rare causes of painless inguinal swelling. The medical history and clinical findings can be used to establish a diagnosis, which can be confirmed using ultrasonography. Management depends on differentiating between spermatic cord hydrocele and scrotal hydrocele and involves considering the type. Treatment options range from conservative measures to surgery, particularly for non-communicating hydroceles that persist beyond 12-18 months or enlarge in size.

CONCLUSION

Encysted hydrocele of the cord is rare and is often mistaken for indirect inguinal hernias in infants and children. This similarity makes the diagnosis challenging and necessitates vigilance from clinicians. Surgical intervention results in optimal outcomes, especially in cases where the hydrocele persists beyond 12-18 months or with size progression.

Disorders of sexual development: structured radiological reporting and practical approach

Disorders of sexual development (DSD) comprise a complex group of conditions with varied clinical presentations, such as atypical genitalia, non-palpable testes, primary amenorrhea, or infertility. Besides being associated with other congenital anomalies, DSDs bear substantial ethical issues regarding assigning the sex of rearing to the child and future fertility options. Establishing the correct diagnosis is essential for the appropriate management of such cases. Various imaging modalities, such as ultrasonography, genitography, and MRI, when complemented with detailed clinical evaluation and karyotyping, are the key to diagnosing the condition. This article attempts to present a concise approach to various patterns of DSD, which will aid radiologists to solve these diagnostic dilemmas.

Canal of nuck hernia with uterus and ovary presenting as inguinal swelling in a female infant

Canal of nuck hernia is rarely reported in pediatric population. We report one such case of a canal of nuck hernia in a 2-month-old girl containing uterus, ovary and small bowel diagnosed on ultrasonography, and which was later confirmed and treated surgically.

Contemporary Review of Masses in the Canal of Nuck

Canal of Nuck masses is a rare occurrence that can cause swelling in the abdominal-inguinal region of females for various reasons. This condition arises due to an abnormal persistence of the processus vaginalis opening. Although Canal of Nuck pathology is not widely known among general surgeons or gynecologists due to its rarity, it has been associated with significant morbidity and requires further research. In this comprehensive review, we aim to summarize the embryology and anatomy of the Canal of Nuck, followed by a description of the various types of masses that can occur in this region. We discuss the clinical presentation and diagnostic workup of Canal of Nuck masses, including imaging modalities and differential diagnoses. Next, we review the surgical management of these masses, including open and laparoscopic approaches. Finally, we discuss the potential complications and long-term outcomes associated with Canal of Nuck pathology. This review aims to compile the presently accessible literature on anomalies occurring in the Canal of Nuck in females, with a particular focus on describing their pathological nature, diagnosis, and management. In summary, this review provides an up-to-date understanding of the pathology, diagnosis, and management of Canal of Nuck masses and aims to raise awareness of this under-recognized surgical challenge among healthcare providers.

US for Evaluation of Acute Abdominal Conditions in Neonates

US is the imaging modality of choice for evaluation of a variety of abdominal conditions, and in recent years it has also become useful and promising as a bedside technique for assessment of acute abdominal conditions in neonates. Bedside US can help, complement, and sometimes replace radiographic or contrast-enhanced studies in critically ill and labile neonates who are difficult to transport to the fluoroscopy suite. Some of the features of bedside US can be applied as point-of-care US (POCUS) of the sick neonate. Some of the abdominal conditions in neonates that can be assessed and monitored with bedside US are necrotizing enterocolitis and its complications, malrotation with a midgut volvulus, segmental volvulus, meconium peritonitis, and complicated inguinal hernia. High-resolution US with the use of 15-MHz and higher-frequency probes allows characterization of the bowel anatomy and features of intestinal abnormalities in neonates in fine detail. Color Doppler US and microvascular imaging improve accuracy in the detection and characterization of bowel vascularity, which is important in the treatment and follow-up of patients with intestinal conditions. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. The slide presentation from the RSNA Annual Meeting is available for this article.

Neonatal Gastrointestinal Emergencies: A Radiological Review

BACKGROUND

Abdominal emergencies in neonates require surgical management in almost all cases and complications may include bowel perforation, sepsis, shock, and even death. Radiological imaging has become a very important aid in the clinical setting as it shortens time to diagnosis.

OBJECTIVE

The objective of this review is to discuss the more prevalent neonatal gastrointestinal emergencies, review appropriate imaging options, and illustrate common radiological presentations of these entities.

CONCLUSION

Despite advancements in imaging techniques, it is important to keep in mind that neonates have a higher susceptibility to the adverse effects of ionizing radiation, and therefore radiography and ultrasonography remain the main diagnostic modalities for ruling out the diseases with the worst prognosis. Other modalities (fluoroscopy, computed tomography, and magnetic resonance imaging) may have limited use in very specific conditions. All providers in an emergency department should be familiar with the basic radiological findings that may indicate a gastrointestinal emergency, especially in health institutions that do not have 24-h radiologist coverage.

Canal of Nuck Abnormalities in Pediatric Female Patients

A groin lump is not an uncommon condition in girls and female infants, and US plays a fundamental role in its exploration. The main pathologic conditions are related to the failure of obliteration of the canal of Nuck. Radiologists should gain a full understanding of the embryology and US anatomy of the inguinal canal before assessing this entity for the first time. An optimal age-adjusted US technique-including examinations at rest and during straining-is essential to help assess the canal of Nuck, diagnose a hernia, and analyze its content. The radiologist must be aware of the various types of hernial content depending on the patient's age, including intestinal, omental, ovarian, or tubouterine hernia, and the US features of each. Incarcerated hernias are common in girls and mostly contain an ovary. In such cases, it is crucial to screen for US signs suggestive of ovarian ischemic damage, thereby calling for urgent surgery. US can also depict a cyst or hydrocele of the canal of Nuck and its complications. Moreover, other rare pathologic conditions involving the inguinal area may be depicted at US, which helps guide appropriate treatment. US is the ideal modality for evaluating an inguinal lump in girls and female infants. Online supplemental material is available for this article. ©RSNA, 2022.

Pearls and Pitfalls of Pediatric Scrotal Imaging

Ultrasonography (US) is the primary imaging modality for the evaluation of pediatric scrotal disease. The ability to obtain exceptional anatomical detail and testicular perfusion information without ionizing radiation makes it the essential tool for evaluating scrotal pain and palpable masses. Challenges arise in both the performance and interpretation of scrotal US in the child. Optimizing imaging parameters and recognizing key differentiating US features help minimize misinterpretations that can lead to poor patient outcomes. Key pearls and pitfalls in pediatric scrotal ultrasound methods and diagnoses are reviewed. Knowledge of what is normal for the various ages of childhood from neonate through adolescence is necessary for accurate US analysis. Imaging evaluation of key causes of the acute painful scrotum including testicular appendage torsion, epididymitis, and testicular torsion are discussed. Sonographic features for the diagnosis of benign and malignant scrotal masses, microlithiasis, and cryptorchidism are reviewed.

The role of scrotal ultrasonography from infancy to puberty

Background

Scrotal ultrasonography is an essential diagnostic tool in daily clinical practice. The availability of new‐generation ultrasound machines characterized by clearly improved image quality, low health cost, and higher patient safety, represents only some characteristics of ultrasound investigation. The usefulness of scrotal ultrasonography is particularly evident in the period of life from infancy to puberty, during which males undergo important morphofunctional changes, and several pathological conditions may occur.

Objectives

This pictorial review primarily aimed to investigate the aspects of ultrasonography related to the normal physiological development of the gonads from mini‐puberty to pubertal onset. This study also aimed to provide an update on the use of ultrasonography in main andrological pathologies that may occur during this period. The conditions that are discussed in depth are: cryptorchidism, inguinoscrotal hernias, and hydrocele in the neonatal phase; acute scrotum, epididymo‐orchitis, and testicular cancers in childhood; and hypogonadism, varicoceles, testicular microlithiasis, and oncohematological pathology in puberty.

Discussion

We provided an ultrasound slant for all the above‐mentioned pathologies while purposely avoiding excessive deepening of the pathogenetic, clinical, and therapeutic aspects. Studying the ultrasound aspects of the gonads also facilitates differential diagnosis between various conditions and represents a good aid in evaluating therapeutic success (e.g., in hypogonadism or postsurgical evaluation of varicoceles and cryptorchidism).

Conclusion

Scrotal ultrasonography is now globally recognized as the necessary completion of clinical–laboratory overview in gonads evaluation. This diagnostic procedure is even more indispensable in the infancy–childhood–puberty period for the evaluation of normal gonadal development as well as diagnosis of other possible diseases.

How embryology knowledge can help radiologists in the differential diagnosis of canal of Nuck pathologies

The Canal of Nuck (CN) is an anatomical structure which is often forgotten. It is the female equivalent of the male processus vaginalis and corresponds to a protrusion of parietal peritoneum that extends from the inguinal canal to labia majora. Radiologists rarely encounter patients with pathology of CN, especially in adult population. It is well known that CN diseases can occur in paediatric patient (especially younger than 5 years of age) and they are associated to high morbidity (for example ovarian hernia with high risk of incarceration and torsion). The aim of our work is to review embryology, anatomy and pathologies of the CN thanks to a multi modal approach-ultrasound (US), Computed Tomography (CT) and Magnetic Resonance imaging (MRI)-to make radiologists more aware of such conditions and guarantee a prompt and correct diagnosis not only in paediatric patients but also in the adult population.

Three‑Dimensional Ultrasonography in Preoperative and Postoperative Volume Assessment of the Undescended Testicle

BACKGROUND Ultrasound (US) is the preferred imaging method for cryptorchidism, but most guidelines indicate that its value is questionable. The aim of this study was to evaluate the clinical value of ultrasonic mobility and testicular atrophy index (TAI) based on three‑dimensional US (3DUS) in preoperative and postoperative assessment of the undescended testis. MATERIAL AND METHODS Data from 158 children with unilateral extraperitoneal cryptorchidism were collected and their diagnoses were surgically confirmed. They were divided into different age groups and into 2 ultrasonic mobility groups: the mobile group (MG) and the restricted group (RG). Differences in sonographic characteristics between different groups were compared. Three-dimensional ultrasound performed with virtual organ computer-aided analysis (VOCAL) was used to determined preoperative and postoperative TAI and the reliability of TAI was analyzed. RESULTS Measurement of testicular volume with the VOCAL method was significantly more reliable than that done with the two-dimensional Lambert method. In all age groups, preoperative testicular volumes were smaller than that in the contralateral scrotal testis and postoperatively, they increased steadily. Both preoperative and postoperative TAI were higher in the RG than in the MG. In the MG, postoperative TAI decreased significantly in all age groups. In the RG, in contrast, effective volume growth was only achieved in patients who had undergone surgery before they reached age 1 year. CONCLUSIONS TAI values determined with 3DUS using the VOCAL technique objectively reflect recovery of testicular volume following surgery for undescended testicle. Ultrasonic mobility evaluation is beneficial for clinical management of the condition.

Pediatric groin lesions: imaging findings

OBJECTIVES

The groin is a complex anatomic region that has traditionally been ignored by radiologists because most lesions can be diagnosed from clinical data and physical examination. Nevertheless, ultrasound examinations of the groin are increasingly being requested to confirm injury or to resolve diagnostic uncertainty. On the other hand, some conditions involving the groin are found only in pediatric patients. This article describes the key imaging findings in pediatric groin injuries, placing special emphasis on the ultrasound appearance.

CONCLUSIONS

Knowledge about conditions that can affect the groin in pediatric patients and the key imaging findings associated with them helps improve the diagnostic performance of ultrasound.

Prenatal Diagnosis of a Cyst of the Canal of Nuck Associated With an Ovarian Cyst and Acute Polyhydramnios

In the female, the canal of Nuck is a tubular fold of parietal peritoneum that travels along with the round ligament through the inguinal canal to its attachment on the labia majora. The canal of Nuck is analogous to the processus vaginalis in the male. In embryonic development, this pathway typically obliterates early in life; however, in some cases, it may partially or completely fail to close. This failure to obliterate can lead to complications ranging from a cyst of the canal of Nuck (also known as a female hydrocele) to herniation and incarceration of abdominal and pelvic organs. There is little information available in the medical literature concerning this rare condition; therefore, it is important for sonographers, physicians, and surgeons to be familiar with this developmental abnormality. This report represents the first prenatal case of a cyst of the canal of Nuck, along with the unique combination of a large left fetal ovarian cyst and acute polyhydramnios. The embryology, incidence, differential diagnosis, management, and treatment of these female conditions are discussed.

Persistence of the processus vaginalis and its related disorders

The processus vaginalis is a blind-ended evagination of the abdominal wall that develops during fetal life and typically undergoes obliteration in early life. Persistence of the processus vaginalis is associated with a number of pathologies including congenital indirect inguinal hernias, communicating hydroceles, funicular and encysted hydroceles, canal of Nuck cysts, and acquired undescended testis. Whilst all are detectable sonographically, there is little educational material relevant to the field of ultrasound with much of the literature directed at surgical and primary care physicians. Furthermore, within the literature there is a lack of consensus on several areas including the anatomy and embryology of the processus vaginalis and the mechanisms behind its obliteration. As such the objective of this paper is to distil the information regarding the persistent processus vaginalis as it is relevant to ultrasound and in doing so address the literature gap for sonographers and sonologists. The anatomy and embryology of the persistent processus vaginalis will be discussed including causative mechanisms for anomalies with their sonographic appearance highlighted.

Canal of Nuck hernias

The canal of Nuck, caused by the failed closure of the processus vaginalis in the female, is the continued outpouching of parietal peritoneum through the inguinal canal to the labia majora. Disorders of the canal of Nuck include hernia and hydrocele. Some canal of Nuck hernias, especially of the ovary, may result in emergent complications such as incarceration, strangulation, and ovarian torsion. Knowledge of canal of Nuck disorders and prompt diagnosis are important to avoid serious complications. Imaging, especially ultrasound, is essential for timely diagnosis, leading to appropriate management and better patient care.

Imaging of diseases of the vagina and external genitalia in children

A wide range of congenital or acquired conditions, some pretty rare, may affect the vulva and vagina in children. Swelling, visible or palpable masses and abnormal discharges are common symptoms of conditions affecting the vulva and/or the lower genital tract. The majority of these diseases are benign. Ultrasonography is pivotal to elucidate the anatomical origin of these conditions and make the diagnosis. Magnetic resonance imaging can be relevant to improve diagnostic confidence and, if needed, to plan more accurate surgical treatment. The aim of this pictorial essay is to review the related imaging findings to help make radiologists familiar with these conditions.

Diagnostic accuracy of preoperative ultrasonography in predicting contralateral inguinal hernia in children: a systematic review and meta-analysis

Objectives

The incidence of children developing metachronous contralateral inguinal hernia (MCIH) is 7–15%. Contralateral groin exploration during unilateral hernia repair can prevent MCIH development and subsequent second surgery and anaesthesia. Preoperative ultrasonography is a less invasive strategy and potentially able to detect contralateral patent processus vaginalis (CPPV) prior to MCIH development.

Methods

We queried MEDLINE, Embase and Cochrane library to identify studies regarding children aged < 18 years diagnosed with unilateral inguinal hernia without clinical signs of contralateral hernia, who underwent preoperative ultrasonography of the contralateral groin. We assessed heterogeneity and used a random-effects model to obtain pooled estimates of sensitivity, specificity and area under the receiver operating characteristic curve (AUC).

Results

Fourteen studies (2120 patients) were included, seven (1013 patients) in the meta-analysis. In studies using surgical exploration as reference test (n = 4, 494 patients), pooled sensitivity and specificity were 93% and 88% respectively. In studies using contralateral exploration as reference test following positive and clinical follow-up after negative ultrasonographic test results (n = 3, 519 patients), pooled sensitivity was 86% and specificity 98%. The AUC (0.984) shows high diagnostic accuracy of preoperative ultrasonography for detecting CPPV, although diagnostic ultrasonographic criteria largely differ and large heterogeneity exists. Reported inguinal canal diameters in children with CPPV were 2.70 ± 1.17 mm, 6.8 ± 1.3 mm and 9.0 ± 1.9 mm.

Conclusion

Diagnostic accuracy of preoperative ultrasonography to detect CPPV seems promising, though may result in an overestimation of MCIH prevalence, since CPPV does not invariably lead to MCIH. Unequivocal ultrasonographic criteria are mandatory for proper diagnosis of CPPV and subsequent prediction of MCIH.

Key Points

• Diagnostic accuracy of preoperative ultrasonography for detection of CPPV in children with unilateral inguinal hernia is high.

• Preoperative ultrasonographic evaluation of the contralateral groin assumedly results in an overestimation of MCIH prevalence.

• Unequivocal ultrasonographic criteria are mandatory for proper diagnosis of CPPV and risk factor identification is needed to predict whether CPPV develops into clinically apparent MCIH.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5625-6) contains supplementary material, which is available to authorized users.

Anatomy and pathology of the canal of Nuck

The canal of Nuck is the female equivalent of the processus vaginalis in the male but is less well known than its male counterpart. It is a rare entity not commonly encountered by radiologists, particularly in the adult population. Knowledge of the embryology and anatomy of the canal of Nuck is essential for identification of the various pathologic conditions that may occur in this location. Moreover, radiologists should be familiar with this entity to compose an appropriate and thorough differential diagnosis of a labial mass/swelling. In this review, we discuss both the anatomy and the more common pathology that can be encountered within it.

Canal of Nuck hernia: a multimodality imaging review

Canal of Nuck abnormalities are a rare but important cause of morbidity in girls, most often those younger than 5 years of age. The canal of Nuck, which is the female equivalent of the male processus vaginalis, is a protrusion of parietal peritoneum that extends through the inguinal canal and terminates in the labia majora. The canal typically obliterates early in life, but in some cases the canal can partially or completely fail to close, potentially resulting in a hydrocele or hernia of pelvic contents. Recognition of this entity is especially important in cases of ovarian hernia due to the risk of incarceration and torsion. We aim to increase awareness of this condition by reviewing the embryology, anatomy and diagnosis of canal of Nuck disorders with imaging findings on US, CT and MRI using several cases from a single institution.