Imaging of groin masses: inguinal anatomy and pathologic conditions revisited

A Single-Center Study on Clinico-Radiological Evaluation of Inguino-Scrotal or Labial Swellings Presenting to a Tertiary Care Set-Up in Central India

Introduction The inguino-scrotal/labial region, anatomically defined as the juncture where the thigh meets the lower abdomen, encompassing the ipsilateral scrotal area in men and the inguino-labial area in women, exhibits a broad spectrum of masses. Traditionally, these swellings were clinically diagnosed with high accuracy, primarily due to the prevalence of simple hernias and hydroceles. However, contemporary observations reveal a surge in complex inguino-scrotal/labial swellings, particularly in referral hospitals, necessitating additional radiological and imaging modalities for precise diagnosis. Our interest in this subject was sparked by the escalating numbers of intricate inguino-scrotal/labial masses encountered in our medical setting, posing challenges for clinical diagnosis in both pediatric and adult populations. Materials and methods A prospective, observational study was conducted over two years (August 2021 to March 2023) involving 210 patients presenting with inguino-scrotal/labial swellings at our institute. Clinical data were meticulously collected using a designed pro forma, following informed consent procedures. Results Among the 210 patients with inguino-scrotal/labial swellings, males predominated (194) compared to females (16). The paediatric age group comprised 84 patients, while 126 were adults. Radiological investigations played a crucial role in diagnosing 40 patients and provided significant additional information in 12 cases. Radiological investigations contributed to the diagnosis in 52 patients (24.76%). The study revealed a spectrum of new entities in the inguino-scrotal/labial region, including malignancies, lymph nodal masses in the groin, and vascular, inflammatory, and congenital lesions, which might have been overlooked if solely relying on clinical parameters for diagnosis. Conclusion Inguino-scrotal/labial swelling patients, especially those facing diagnostic dilemmas or harbouring complex lesions, should undergo radiological assessment as an indispensable criterion, particularly when such facilities are readily accessible.

A rare case of De Garengeot hernia: CT findings

We report a case of "De Garengeot's hernia" (DGH), a rare condition that occurs when the inflamed appendix is localized inside a femoral hernia. The appendix may be involved in inflammatory or necrotic processes and the treatment is emergency surgery. It is usually discovered by chance during surgery. It occurs in 0.5%-5% of all femoral hernias. In 0.08%-0.13% of cases, the appendix can present inflammatory or necrotic processes due to the narrowness of the neck of the femoral canal; in these cases, an emergency surgery is required through a no standard surgical procedure. In the other cases, it is usually found accidentally during surgical repair of the hernia or more rarely diagnosed preoperatively by CT. Therefore, the purpose of our study is to report a case of DGH describing CT main findings in order to improve the preoperative diagnosis.

Hydrocele and endometriosis of the canal of Nuck in two adults: a look at the imaging features

We present a report of two adult females who presented to the surgery clinic at different time frames in our hospital with a swelling in the inguinal region. The swelling was painful for one of our patients. The first patient was evaluated with a contrast-enhanced CT and an MRI, while the second patient underwent a ultrasonography and an MRI. Imaging revealed the structure to be cystic in nature and confirmed the diagnosis as a hydrocele of the canal of Nuck in both patients. Our second patient was also found to have concomitant endometriosis, with internal septations seen in the hydrocele. Aspiration revealed altered blood with haemosiderin deposition, which established a diagnosis of endometriosis of the canal of Nuck. The first patient underwent excision, while the second patient refused a surgical approach and opted for medical management for endometriosis.

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.

Hydrocele of the Canal of Nuck: A Review

Canal of Nuck abnormality is a rare surgical condition. The pathologies are mostly encountered in young girls, less than five years of age. The incidence is even less in adults. Various pathologic conditions related to the failure of processus vaginalis obliteration can occur, involving herniation of intraabdominal structures including intestinal and genital contents such as the uterus, fallopian tube, and ovary and hydrocele of the canal of Nuck.

According to its rarity, hydrocele of canal of Nuck is often misdiagnosed for common groin masses. This review summarizes and simplifies embryology, the pathophysiology of the canal of Nuck abnormalities, imaging findings, and treatment options with emphasis on the hydrocele. 

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.

Cyst and endometriosis of the canal of Nuck: rare differentials for a female groin mass

Cyst of the canal of Nuck is a rare abnormality of the female inguinal canal that can present similarly to a hernia. If incompletely obliterated, the patent canal of Nuck may predispose to an inguinal hernia or hydrocele due to direct communication with the abdominal cavity. Such defects are normally detected and repaired in early childhood but can also present later in adult life. We report the case of a 44-year-old woman who presents with a fluctuant, mobile and irreducible left-sided groin mass. Ultrasound of the groin identified a cystic structure in the canal of Nuck. The patient underwent successful open herniorrhaphy with excision of the cyst and mesh repair of the inguinal canal. Subsequent histopathological examination also revealed concurrent endometriosis of the canal of Nuck. A systematic approach to differential diagnoses for a female groin mass, further investigations and management are discussed.

Female pediatric inguinal hernia: uterine deviation toward the hernia side

PURPOSE

We aimed to clarify the frequency and the clinical significance of deviation of the uterus in female pediatric inguinal hernia.

METHODS

We retrospectively evaluated the data of 94 female pediatric inguinal hernia cases that were treated by laparoscopic percutaneous extraperitoneal closure. We assessed for correlations between uterine deviation and age, body weight, the size of the hernia orifice, and the presence of contralateral processus vaginalis (PV) patency.

RESULTS

Eighty-four of 94 cases were diagnosed with unilateral inguinal hernia. A total of 62 (73.8%) of these had uterine deviation to the hernia side (Group D); 22 (26.2%) had no deviation to the hernia side (Group N) (P < 0.001). Group D cases were significantly younger than those in Group N (P = 0.0351). There was no difference in body weight, size of the hernia orifice, or contralateral PV patency between the two groups.

CONCLUSION

The incidence of uterine deviation toward the hernia side was statistically significant. It is important to recognize that female pediatric inguinal hernia repair carries an increased risk of ovarian and fallopian tube damage, because these appendages are close to the hernia orifice as a result of the uterine deviation.

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.

[Hydrocele of the canal of Nuck detected during infertility evaluation: an atypical case report]

L´hydrocèle du canal de Nuck est une pathologie rare de la femme, souvent découverte durant l´enfance. Cette présentation rapporte un cas rare d´hydrocèle découverte à l´âge adulte au cours d´un bilan d´infertilité. A l´admission au service, la patiente a rapporté une tuméfaction inguinale droite chronique non douloureuse. L´imagerie a été typique d´une hydrocèle du canal de Nuck. L´échographie a retrouvé une formation kystique avec quelques fin septas et l´'imagerie par résonance magnétique (IRM) n´a pas retrouvé de communication avec le péritoine. Avec les mêmes moyens d´imagerie, un utérus bicorne non cloisonné a été découvert pouvant rentrer dans le cadre de son bilan d´infertilité. Le but principal de ce travail est de faire connaitre l´imagerie typique de l´hydrocèle du canal de Nuck un diagnostic peu connu et de le faire intégrer parmi les diagnostics différentiels des tuméfactions inguinales chez la femme.

Infantile presentation of the canal of Nuck hernia containing uterus and ovary: a case report

Indirect inguinal hernias of the canal of Nuck containing the uterus and the ovary is rare entity in girls presenting as labia major masses at infancy and early childhood. Authors present a case of the canal of Nuck hernia in a 5-month-old girl presented as palpable lump in the right labia majora which was diagnosed by ultrasonography. Ultrasound is the noninvasive diagnostic modality of choice in for evaluation of palpable external genital masses in children.

Rare encounter: hydrocoele of canal of Nuck in a Scottish rural hospital during the COVID-19 pandemic

We report the case of a 32-year-old woman who presented with reducible indirect inguinal hernia and a challenging constellation of symptoms, signs and radiographic findings. Surgical approach superseded conservative management when the patient's abdomen became acute, with a rising lactate and haemodynamic instability. Specifically, the presence of a fluid collection was concerning for sinister acute pathology. Our patient was rediagnosed intraoperatively with hydrocoele of canal of Nuck. This so-called 'female hydrocoele' is an eponymous anatomical rarity in general surgery, presenting as an inguinolabial swelling with variable clinical profile. Hydrocoele of canal of Nuck takes origin from failure of transitory reproductive anlagen to regress and is thus analogous to patent processus vaginalis. Its true incidence is speculative, with just several hundred cases globally. We aim to provide insights into surgical patient management for a rare entity during the COVID-19 outbreak, from the unique perspective of a small rural hospital in Scotland.

Spermatic Cord Lipoma-A Review of the Literature

Introduction: A spermatic cord lipoma is found in 20–70% of all inguinal hernia repairs. The clinical picture of an inguinal hernia with bulging and pain but without an actual indirect hernia sac may become manifest in up to 8% of these cases. Missed spermatic cord lipoma can result in recurrence or pseudo-recurrence. This review presents the relevant literature on this topic.

Materials and Methods: A systematic search of the available literature was performed in February 2020 using Medline, PubMed, Google Scholar, Scopus, Embase, Springer Link, and the Cochrane Library, as well as a search of relevant journals and reference lists. Forty-two publications were identified as relevant for this topic.

Results: Spermatic cord lipoma seems to originate from preperitoneal fatty tissue within the internal spermatic fascia in topographical proximity to the arteries, veins, lymphatics, nerves, and deferent duct within the spermatic cord. Reliable diagnosis cannot be made clinically, but rather with ultrasound, CT, or MRI. In the absence of a real hernia sac, a spermatic cord lipoma is classified as a lateral inguinal hernia with a defect size <1.5 cm according to the European Hernia Society (EHS LI). Missed or inadequately treated spermatic cord lipoma results in recurrence or pseudo-recurrence. Since spermatic cord lipoma obtains its vascular supply from the preperitoneal space, it can be reduced or resected.

Conclusion: Spermatic cord lipoma is a common finding in inguinal hernia repairs and must be properly diagnosed and treated with care respecting the anatomy of the spermatic cord.

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.

Canal of Nuck Abnormalities

Canal of Nuck abnormalities are underrecognized causes of labial masses with potential adverse outcomes. The 2 main categories of canal of Nuck abnormalities are hernias and hydroceles. There are 3 types of canal of Nuck hydroceles: communicating, encysted, and bilocular. Canal of Nuck hernia contents vary, but those containing ovaries need urgent medical attention because of an increased risk of ischemia. Ultrasound can establish a definite diagnosis in all cases. This article reviews the embryologic characteristics, anatomy, pathologic characteristics, and imaging features of these abnormalities while providing a clear pictorial depiction of various unique hernias and hydroceles seen with this entity.

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.

Four "fine" messages from four kinds of "fine" forgotten ligaments of the anterior abdominal wall: have you heard their voices?

On the posterior aspect of the anterior abdominal wall, there are four kinds of "fine" ligaments. They are: the round ligament of the liver, median umbilical ligament (UL), a pair of medial ULs, and a pair of lateral ULs. Four of them (the round ligament, median UL, and paired medial ULs) meet at the umbilicus because they originate from the contents of the umbilical cord. The round ligament of the liver originates from the umbilical vein, the medial ULs from the umbilical arteries, and the median UL from the urachus. These structures help radiologists identify right-sided round ligament (RSRL) (a rare, but surgically important normal variant), as well as to differentiate groin hernias. The ligaments can be involved in inflammation; moreover, tumors can arise from them. Unique symptoms such as umbilical discharge and/or location of pathologies relating to their embryology are important in diagnosing their pathologies. In this article, we comprehensively review the anatomy, embryology, and pathology of the "fine" abdominal ligaments and highlight representative cases with emphasis on clinical significance.

Groin abnormalities: ultrasonographic and clinical findings

Groin lesions can be classified as neoplastic or non-neoplastic. Neoplastic lesions include lipoma, epidermoid cyst, angiomyofibroblastoma-like tumor, liposarcoma, and synovial sarcoma, as well as metastases from lymphoma, neuroendocrine carcinoma, and carcinomas of the lung, breast, urinary bladder, ovary, vulva, and colon. Non-neoplastic lesions include hernias, round ligament varices, endometriosis, Kimura disease, Castleman disease, hematoma, and inflammation. Because the clinical implications and therapeutic strategies for groin lesions vary depending on the cause, the ability to noninvasively differentiate among etiologies is very important. Although there is substantial overlap in ultrasonographic findings across various groin lesions, some ultrasonographic features, along with clinical characteristics, may suggest a specific diagnosis. Familiarity with the ultrasonographic and clinical features of various groin lesions facilitates accurate diagnosis and treatment.

Use of a Novel Open Posterior Wall Technique for Laparoscopic Excision of Hydrocele of the Canal of Nuck in an Adult Female: Case Report

Complete surgical excision is the standard treatment for hydrocele of the canal of Nuck. We developed a novel open posterior wall technique for laparoscopic transabdominal pre-peritoneal (TAPP) excision. A 38-year-old woman with a 5-month history of a painless reducible lump in the right groin had recently noticed a slight increase in the size of lump. Computed tomography showed a simple cystic lesion measuring 30 × 27.5 mm. We performed laparoscopic excision of the hydrocele by using the TAPP approach and the open posterior wall technique developed by us. Complete excision of the hydrocele was satisfactorily performed because the region from the external inguinal ring to the periphery could be clearly observed. After an uneventful postoperative course, the patient was discharged. Laparoscopic TAPP excision with open posterior wall technique was useful for complete excision of hydrocele of the canal of Nuck.

Effect of inguinal hernia on the thickness and blood flow of spermatic cord in boys

Objective

To evaluate the effect of inguinal hernia (IH) on the spermatic cord using spermatic cord ultrasonography (SCU).

Methods

From January 2016 to January 2017, boys with IH who received SCU at the start of open herniorrhaphy (OH) were enrolled in this study. The age and weight at SCU, width of the spermatic cord (SC-W), peak systolic velocity (PSV) in the spermatic artery (SA-PSV) and velocity in the pampiniform plexus (PP-V), and the interval between the initial and the second OH in boys with metachronous inguinal hernia (MIH) were recorded, and the relationship among them was studied. Boys with unilateral IH comprised the IH group, and boys with MIH comprised the MIH group. Boys with polydactylism served as the control. One-way analysis of variance tested the differences among groups. Spearman's r tested the relationship between SC-W in the MIH group and the interval.

Results

A total of 80 boys were enrolled in this study (IH group 29, MIH group 26, and control group 25). SA-PSV and PP-V in the hernia side were faster and slower than the control, respectively. There was no significant difference in PP-V and SA-PSV of the treated side in the MIH group and in the control group. After herniorrhaphy, SC-W was tapered down to normal size. SC-W, SA-PSV, and PP-V in the treated side were all highly correlated to the interval in a curvilinear manner.

Conclusion

PSV was positively correlated with SC-W in boys with IH, and PP-V was negatively correlated; herniorrhaphy could reverse the impairment.

Lipoma of the fossa femoralis mimicking a femoral hernia. Report of 2 cases

INTRODUCTION

Lipoma of the femoral fossa is uncommon. Often asymptomatic, femoral lipoma may growth within the circumscribed space of the femoral fossa causing pain and discomfort. A worsening pain caused by a lipomatous mass in the femoral area is a clinical feature that can mislead the diagnosis, resembling the more common condition of femoral hernia.

METHODS

Two cases of symptomatic lipomas of the femoral fossa mimicking an incarcerated femoral hernia are presented. In both, Caucasian female, patients clinical examination and ultrasound of the femoral region revealed a painful neoplasm suspected for incarcerated femoral hernia.

RESULTS

Intraoperatively, a mass of encapsulated fat arising from the bottom of the fossa femoralis was found. No visceral protrusion through the femoral ring could be documented. The neoplasms were removed in toto. Histology of the excised specimens evidenced the diagnosis of femoral lipomas suffering by chronic compressive damages. In a midterm postoperative follow up, both patients were symptom- free.

DISCUSION

A correct preoperative diagnosis of femoral lipoma is challenging, even following an accurate diagnostic pathway. The cases highlighted herewith seem to confirm that lipoma of the femoral fossa can be mistaken with a femoral hernia.

CONCLUSIONS

The clinical and histological features evidenced could result helpful in the differentiation of a lipomatous mass of the femoral fossa from a genuine femoral hernia.

Ultrasound evaluation of inguinoscrotal pain: an imaging-based review for the ultrasonographer

Emergencies involving the inguinal region and scrotum are common and can be caused by a plethora of different causes. In most cases, such conditions have nonspecific symptoms and are quite painful. Some inguinoscrotal conditions have high complication rates. Early and accurate diagnosis is therefore imperative. Ultrasound is the method of choice for the initial evaluation of this vast range of conditions, because it is a rapid, ionizing radiation-free, low-cost method. Despite the practicality and accuracy of the method, which make it ideal for use in emergency care, the examiner should be experienced and should be familiarized with the ultrasound findings of the most common inguinoscrotal diseases. On the basis of that knowledge, the examiner should also be able to make an accurate, direct, precise report, helping the emergency room physician make decisions regarding the proper (clinical or surgical) management of each case. Here, we review most of the inguinoscrotal conditions, focusing on the imaging findings and discussing the critical points for the appropriate characterization of each condition.

Multidetector CT of iatrogenic and self-inflicted vascular lesions and infections at the groin

Abstract

The number and complexity of endovascular procedures performed via either arterial or venous access are steadily increasing. Albeit associated with higher morbidity compared to the radial approach, the traditional common femoral artery remains the preferred access site in a variety of cardiac, aortic, oncologic and peripheral vascular procedures. Both transarterial and venous cannulation (for electrophysiology, intravenous laser ablation and central catheterisation) at the groin may result in potentially severe vascular access site complications (VASC). Furthermore, vascular and soft-tissue groin infections may develop after untreated VASC or secondarily to non-sterile injections for recreational drug use. VASC and groin infections require rapid diagnosis and appropriate treatment to avoid further, potentially devastating harm. Whereas in the past colour Doppler ultrasound was generally used, in recent years cardiologists, vascular surgeons and interventional radiologists increasingly rely on pelvic and femoral CT angiography. Despite drawbacks of ionising radiation and the need for intravenous contrast, multidetector CT rapidly and consistently provides a panoramic, comprehensive visualisation, which is crucial for correct choice between conservative, endovascular and surgical management. This paper aims to provide radiologists with an increased familiarity with iatrogenic and self-inflicted VASC and infections at the groin by presenting examples of haematomas, active bleeding, pseudoaneurysms, arterial occlusion, arterio-venous fistula, endovenous heat-induced thrombosis, septic thrombophlebitis, soft-tissue infections at the groin, and late sequelae of venous injuries.

Teaching Points

• Complications may develop after femoral arterial or venous access for interventional procedures.

• Arterial injuries include bleeding, pseudoaneurysm, occlusion, arteriovenous fistula, dissection.

• Endovenous heat-induced thrombosis is a specific form of iatrogenic venous complication.

• Iatrogenic infections include groin cellulitis, abscesses and septic thrombophlebitis.

• CT angiography reliably triages vascular access site complications and groin infections.

Canal of Nuck hernia containing pelvic structures presenting as a labial mass

Although rare, canal of Nuck hernias containing pelvic structures or peritoneal contents are an important differential consideration in the pediatric setting of a palpable labial mass. This diagnosis should be considered early as there is a high rate of associated ovarian torsion in the setting of incarcerated hernias containing ovaries. Early sonographic evaluation is crucial to establish the diagnosis. We report an extremely rare case of a 2-month-old who presented with right labial swelling due to a canal of Nuck hernia containing the uterus, the ipsilateral ovary, and the fallopian tube.

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.

Clinics in diagnostic imaging (183)

Hydrocoele of the canal of Nuck is a rare condition in adult women caused by a failure of complete obliteration of the canal of Nuck. It may be likened to a patent processus vaginalis in men. In most cases, the diagnosis is made during surgery as it is often mistaken for an inguinal hernia. We report a case where the diagnosis of this condition was made preoperatively on imaging. The salient anatomy, clinical features, radiological images and surgical management are discussed and the medical literature reviewed.

Imaging of Uncommon Causes of Large-Bowel Obstruction

OBJECTIVE

The most common causes of large-bowel obstruction (LBO) are colon carcinoma and volvulus. Nevertheless, the increased frequency of the condition and widespread use of diagnostic imaging have revealed uncommon causes of LBO. We review the imaging features of the unusual causes of LBO on several imaging modalities, with particular emphasis on CT, along with the current literature.

CONCLUSION

We propose an algorithmic approach to the radiologic evaluation of the uncommon causes of LBO.

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.

Radiological Findings in Persistent Müllerian Duct Syndrome: Case Report and Review of Literature

This case involved a 36-year-old adult male who presented with an unusual inguinal hernia in which the uterus and fallopian tubes were identified as contents of the inguinal hernia sac. These findings reflected a rare autosomal recessive developmental syndrome known as PMDS (persistent Müllerian duct syndrome). The diagnosis was established and confirmed via radiological-mainly MRI-investigation.

Inguinoscrotal hernia in infants: Three case reports in ultrasound diagnosis

An inguinal hernia occurs when an intestinal loop or part of the omentum or genital organs passes into the scrotal cavity or labia through an incompletely obliterated processus vaginalis. Inguinal hernias are most common in preterm neonates, especially at 32-weeks gestation. Content of hernia is mostly bowel and ovary/testicles. Presence of uterus in herniated sac is rare, and only few cases are reported in literature. Hernia is more frequently located on the right side because the right processus vaginalis closes later than the left. Physical examination is sufficient to enable diagnosis in most cases. Ultrasound examination is indicated in patients with inconclusive physical findings, in patients with acute scrotum, and to investigate contralateral involvement in patients in whom only a unilateral hernia is clinically evident. Routinely, color or power Doppler imaging is used in inguinal-scrotal hernia to investigate intestinal and testicular/ovarian perfusion. Urgent surgery is indicated in patients with an akinetic dilated bowel loop (a sign of strangulation) or impaired testicular/ovarian perfusion.

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

Bulging of the inguinal region is a frequent complaint in the pediatric population and sonographic findings can be challenging for radiologists. In this review we update the sonographic findings of the most common disorders that affect the inguinal canal in neonates and children, with a focus on the processus vaginalis abnormalities such as congenital hydroceles, indirect inguinal hernias and cryptorchidism, illustrated with cases collected at a quaternary hospital during a 7-year period. We emphasize the importance of correctly classifying different types of congenital hydrocele and inguinal hernia to allow for early surgical intervention when necessary. We have systematically organized and illustrated all types of congenital hydrocele and inguinal hernias based on embryological, anatomical and pathophysiological findings to assist readers in the diagnosis of even complex cases of inguinal canal ultrasound evaluation in neonates and children. We also present rare diagnoses such as the abdominoscrotal hydrocele and the herniation of uterus and ovaries into the canal of Nuck.

Lipoma in the femoral triangle

The differential diagnosis of a lipoma in the femoral region will include a femoral hernia and vice-versa or both may coexist.

Cysts of the canal of Nuck: A rare sonographic diagnosis

The canal of Nuck is a remnant of a peritoneal evagination associated with the round ligament in women. Rarely, the canal of Nuck can remain patent allowing for development of cysts. These cysts are difficult to diagnose due to their rare incidence and because they are often mistaken for other causes of inguinal pain in women. This case series of three women presenting with groin or labial masses highlights the role of sonography as the primary imaging modality in the diagnosis of canal of Nuck cysts. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:175-178, 2017.

Ectopic ovary with torsion: uncommon diagnosis made by ultrasound

Ultrasound is an important diagnostic tool in inguinal hernia and in the evaluation of the contents of the hernia sac. This report presents a case in which ultrasound revealed a herniated ectopic ovary, complicated by torsion of its vascular pedicle, in the right labia majora. We also present a brief discussion of ovarian hernia, its potential complications, and the treatments available.

US of the Inguinal Canal: Comprehensive Review of Pathologic Processes with CT and MR Imaging Correlation

Ultrasonography (US) has a fundamental role in the initial examination of patients who present with symptoms indicating abnormalities of the inguinal canal (IC), an area known for its complex anatomy. A thorough understanding of the embryologic and imaging characteristics of the contents of the IC is essential for any general radiologist. Moreover, an awareness of the various pathologic conditions that can affect IC structures is crucial to preventing misdiagnoses and ensuring optimal patient care. Early detection of IC abnormalities can reduce the risk of morbidity and mortality and facilitate proper treatment. Abnormalities may be related to increased intra-abdominal pressure, which can result in development of direct inguinal hernias and varicoceles, or to congenital anomalies of the processus vaginalis, which can result in development of indirect hernias and hydroceles. US is also helpful in assessing postoperative complications of hernia repair, such as hematoma, seroma, abscess, and hernia recurrence. In addition, it is often the modality initially used to detect neoplasms arising from or invading the IC. US is an important tool in the examination of patients suspected of having undescended testes or posttraumatic testicular retraction and is essential for the examination of patients suspected of having torsion or infectious inflammatory conditions of the spermatic cord. Online supplemental material is available for this article. ^©RSNA, 2016.

Canal of Nuck Hernia in a Female Infant Containing Uterus, Bilateral Adnexa and Bowel

BACKGROUND

The canal of Nuck is a fold of peritoneum that invaginates into the inguinal canal and closes at or just before birth. If the canal of Nuck remains open in female infants, herniation of the uterus, adnexa and/or bowel loops may arise through the inguinal canal into the labia majora.

CASE REPORT

The present case is a 12-week-old female infant with complaints of left groin swelling and discomfort. Ultrasonographic examination revealed a left inguinal hernia containing both adnexa (ovaries and fallopian tubes), uterus and small bowel loops with fluid.

CONCLUSION

A hernia containing ovary and uterus should be considered as a possible cause in a female infant with a groin mass. Ultrasonography of the inguinal mass lesions should be performed routinely in a female infant for accurate diagnosis.

Inguinoscrotal Pathology on Computed Tomography: An Alternative Perspective

Computed tomography (CT) is not the imaging technique of choice to assess inguinoscrotal pathology, as magnetic resonance or ultrasonography have superior soft tissue contrast resolution and do not involve gonadal exposure to ionizing radiation. However, testicular and inguinoscrotal pathology may be found both as an extension of intra-abdominal processes or incidentally on CT scans requested for other reasons. CT also plays a role in the evaluation of testicular injury when associated to pelvic trauma and in perineal infections with scrotal extension. A pictorial review of testicular and inguinoscrotal involvement in vascular, neoplastic, traumatic, infectious, or inflammatory diseases and in complications of abdominal surgeries is presented. Additionally, the CT appearance of several congenital anomalies and benign processes is depicted.

Sonographic evaluation of athletic pubalgia

Athletic pubalgia, or "sports hernia", represents a constellation of pathologic conditions occurring at and around the pubic symphysis. These injuries are primarily seen in athletes or those involved in athletic activity. In this article, we review the sonographic appearance of the relevant complex anatomy, scanning technique for ultrasound evaluation of athletic pubalgia, and the sonographic appearances of associated pathologic conditions.

Hydrocele of the Canal of Nuck (Female Hydrocele): A Rare Differential for Inguino-Labial Swelling

The inguinal canal is traversed by the spermatic cord in men and the round ligament of uterus in women. The round ligament is attached to the uterine cornu near the origin of fallopian tube at one end and to the ipsilateral labia majora at the other. The round ligament accompanies a pouch of parietal peritoneum in the inguinal canal, which is known as 'canal of nuck'. It is analogous to the processus vaginalis in males. Incomplete obliteration of the peritoneal pouch causes indirect inguinal hernia or hydrocele of the canal of nuck; a very rare condition in women. As these types of cases are rarely seen in surgical practice we present a case of such little-known developmental disorder in a three-year-old girl. She presented with irreducible, tender right inguino-labial swelling with tachycardia simulating incarcerated inguinal hernia, which necessitates emergency surgical exploration. On exploration it was found to be an encysted hydrocele of canal of nuck; so although rare, this entity should be considered in differential diagnosis in a female child presented with inguino-labial swelling.