Bilateral hydrocele of the canal of Nuck: A case report

Shankar Adhikari (SA), Om Prakash Bhatta (OPB) = Study concept, Data collection, and management of the patient. Sabita Chand (SC), Ashish Tiwari (AT) = Writing - original draft preparation and editing. SA = Senior author and Manuscript reviewer. All authors critically reviewed, revised, and contributed to the final article. All authors read and approved the final manuscript.

Ethical approval for a case report is exempt at the authors institution. It is only necessary to obtain the patient's consent.

Written informed consent was obtained from the patient's parents/legal guardian for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

None.

Not applicable.

Om Prakash Bhatta.

In females, the ovarian ligament develops from the cranial portion of the gubernaculum during embryonic development, while the round ligament of the uterus is formed from its caudal part. As the round ligament traverses from the inguinal canal into the labium majus, it is accompanied by a peritoneal fold called the “processus vaginalis,” which is also commonly referred to as the canal of Nuck. Typically, the canal of Nuck undergoes closure within the first year of life. However, if complete closure fails to occur, it can lead to the development of an indirect inguinal hernia or hydrocele of the canal of Nuck. [ 1 , 2 , 4 ] The medical literature discusses three distinct anatomical variations in the hydrocele of the canal of Nuck. The most prevalent form, known as type 1, resembles an encysted hydrocele and does not communicate with the peritoneal cavity. Type 2 closely resembles congenital hydrocele in males, involving open communication with the peritoneal cavity and the potential for herniation. The least common variation, type 3, occurs when there is partial constriction at the deep ring, causing the distal part to descend into the inguinal canal while the proximal part remains retroperitoneal. [ 5 ] Typically, the hydrocele of the canal of Nuck manifests as a painless or moderately painful (when tense or infected), translucent, and non-reducible lump in the inguino-labial region. [ 1 ] A high index of suspicion is required by the treating surgeon to avoid misdiagnosis. Differential diagnoses for hydrocele of the canal of Nuck include indirect inguinal hernia, femoral hernia, lymphadenopathy, Bartholin's cyst, epidermal cysts, infection or abscess, endometriosis of the round ligament, and both benign and malignant neoplasms. [ 2 , 6 , 7 ] In cases where the history is not sufficient to make a diagnosis with reasonable confidence, final confirmation only takes place intraoperatively. Imaging studies may be utilized to aid in the pre-operative diagnosis. [ 2 , 4 , 8 ] USG can serve as a primary diagnostic modality where hydrocele is typically visualized as a well-defined hypoechoic or anechoic mass, resembling a sausage or comma shape. It is located superficially and medially to the pubic bone within the inguinal canal and exhibits posterior acoustic enhancement due to its translucency. [ 7 , 9 ] Magnetic resonance imaging (MRI) findings include a well-defined, thin-walled, sausage-shaped cystic lesion in the inguinal region that is hyperintense on T2 and hypointense on T1. [ 7 , 10 ] It is frequently associated with inguinal hernias, which further adds to the dilemma in diagnosis. [ 11 , 12 ] Management of hydrocele of the canal of Nuck involves surgery, which is necessary for final diagnosis and treatment. [ 8 ] Surgical repair involves exploring the inguinal canal, performing resection and proximal ligation of the hydrocele, and repairing any defects in the parietal peritoneum. The choice between open or laparoscopic procedures depends on factors such as the type of defect, the availability of technology, and the preferences of the treating surgeon or institution. [ [13] , [14] , [15] ] As hydrocele is commonly associated with indirect inguinal hernias, dissection must be done up to the deep inguinal ring along with high ligation of the neck of the peritoneal pouch. [ 8 , 11 ] A similar report by Baral et al. describes a 25-year-old female with bilateral inguinolabial swelling, which was clinically diagnosed as bilateral irreducible inguinal hernias before being diagnosed with the canal of Nuck hydrocele intraoperatively. It was treated with the removal of the cystic component of the bilateral canal and tissue repair of the left indirect inguinal hernia. [ 11 ]

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Since bilateral hydrocele of the canal of Nuck is a rare condition, our case highlights the need to consider it as a differential diagnosis in a female child with inguinal swelling. Accurate preoperative diagnosis necessitates an understanding of the anatomy and is based on physical examination and, if available and deemed necessary, USG and MRI. Contralateral hydrocele or inguinal hernia should also be considered before proceeding to surgical excision, which is essential for a definitive diagnosis and treatment of choice.

The canal of Nuck is an embryological anomaly in which the processus vaginalis remains patent within the inguinal canal of a female. Owing to this abnormal communication, a potential space is formed between the peritoneal cavity, female inguinal canal, and labia majora. [ 1 ] It is a rare finding in females and occurs most commonly in pediatric patients. [ 2 ] Although there might be a wide range of differential diagnoses for inguinal swelling in a female, the canal of Nuck hydrocele might be easily missed by clinicians and radiologists because of its rare occurrence, necessitating a high level of vigilance among clinicians and radiologists to avoid unnecessary investigations and prevent any complications. This case has been reported in line with the SCARE checklist. [ 3 ]

A two-year-old girl presented to our surgical outpatient department (OPD) with painless swelling in the bilateral inguinal region. Her mother had noticed swelling in the bilateral groin six months previously. There were no complaints of abdominal pain, abdominal distension, or vomiting. Local examination revealed a well-defined pear-shaped swelling in the bilateral inguino-labial region. The swellings were irreducible, fluctuant, and had normal overlying skin. It was not tender and did not elicit expansive impulses. The other examination findings were unremarkable. Her complete blood count and urinalysis results were within normal limits. A differential diagnosis of inguinal hernia or hydrocele was made based on the aforementioned clinical picture, and the patient was scheduled for elective surgery. The inguinal canal was explored using a transverse skin-crease incision. The cyst extended down to the labia majora, and it was clearly seen as an encysted hydrocele of the canal of Nuck, without any evidence of an associated inguinal hernia. The cyst was carefully dissected from the round ligament, ligation of the canal of Nuck was performed near the deep inguinal ring, and the wound was closed in layers. This procedure was repeated on the other side. The post-operative period was uneventful, and there was no evidence of recurrence in the last six months of follow-up ( Fig. 1 , Fig. 2 , Fig. 3 ). Fig. 1 Intraoperative inguinal exploration revealed canal of Nuck hydrocele which was corrected with bilateral excision with high pouch ligation. Fig. 1 Fig. 2 Intraoperative inguinal exploration revealed canal of Nuck hydrocele which was corrected with bilateral excision with high pouch ligation. Fig. 2 Fig. 3 Gross specimen showing blind-ending, fluid-filled structure consistent with canal of Nuck hydrocele. Fig. 3 Intraoperative inguinal exploration revealed canal of Nuck hydrocele which was corrected with bilateral excision with high pouch ligation. Intraoperative inguinal exploration revealed canal of Nuck hydrocele which was corrected with bilateral excision with high pouch ligation. Gross specimen showing blind-ending, fluid-filled structure consistent with canal of Nuck hydrocele.

OPD outpatient department USG ultrasonography MRI Magnetic resonance imaging outpatient department ultrasonography Magnetic resonance imaging

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