Hydrocele of the Canal of Nuck: A report of five cases.

Shankar Adhikari (SA), Om Prakash Bhatta (OPB) = Study concept, Data collection, and management of the patient. SA, OPB = 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 was exempt from the authors' institution. The patients agreed to participate in the study. Informed consent was obtained from all the patients prior to the study.

Written informed consent was obtained from the patients' parents for the publication of this case series and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal upon request.

None.

Not applicable.

The canal of the Nuck hydrocele should be considered in the differential diagnosis of all female pediatric patients presenting with inguinolabial masses. Despite its potential for severe morbidity if left untreated, the canal of Nuck hydrocele is often under-recognized and misdiagnosed. A high index of suspicion from the treating surgeon should precede prompt ultrasound examination, which can help make an accurate diagnosis. Surgical treatment involves dissecting the hydrocele from the round ligament followed by ligation of the canal of Nuck near the deep inguinal ring.

The hydrocele of the Canal of Nuck develops from the failure of complete obliteration of the processus vaginalis in female patients. The canal of the Nuck hydrocele has been classified into three types: communicating, encysted, and bilocular hydroceles, with encysted being the most common variant that resembles an encysted hydrocele and does not communicate with the peritoneal cavity [ 1 , 7 ]. Most cases are asymptomatic and are usually found incidentally by parents or children as painless swelling in the inguinolabial region in children and adolescents ( Fig. 3 ). Some patients may complain of dull aching pain, particularly in neglected cases or when complications occur. [ 6 , 8 ] Fig. 2 Intraoperative inguinal exploration of case #1 revealed a canal of Nuck hydrocele, which was corrected with excision and high pouch ligation. Fig. 2 Fig. 3 Anatomy of the inguinal canal with a physiologically obliterated canal of Nuck and the potential sites of cyst when the canal remains patent. [ 6 ]. [Prodromidou A. et al., Fig. 2 . From Prodromidou A. et al. (2020) Cyst of the Canal of Nuck in adult females: A case report and systematic review. Biomedical Reports, 12(6):333–338. Retrieved October 11, 2023, from Biomedical Reports Spandidos Publications. doi: https://doi.org/10.3892/br.2020.1295 Used with permission from Biomedical Reports Spandidos Publications.] Fig. 3 Intraoperative inguinal exploration of case #1 revealed a canal of Nuck hydrocele, which was corrected with excision and high pouch ligation. Anatomy of the inguinal canal with a physiologically obliterated canal of Nuck and the potential sites of cyst when the canal remains patent. [ 6 ]. [Prodromidou A. et al., Fig. 2 . From Prodromidou A. et al. (2020) Cyst of the Canal of Nuck in adult females: A case report and systematic review. Biomedical Reports, 12(6):333–338. Retrieved October 11, 2023, from Biomedical Reports Spandidos Publications. doi: https://doi.org/10.3892/br.2020.1295 Used with permission from Biomedical Reports Spandidos Publications.] Symptoms depend on the size of the swelling, presence of complications, and existence of an associated hernia. The diagnosis is mainly clinical; however, when the surgeon is uncertain, ultrasonography can be used for preoperative diagnosis and anatomical characterization of the swelling and the presence of a hernia and its contents. [ 7 , 9 ] Ultrasonography (USG) is preferred because of its ability to visualize superficial lesions as well-defined hypoechoic or anechoic, sausage- or comma-shaped masses, located superficially and medially to the pubic bone in the inguinal canal, with enhanced posterior translucency. [ 10 , 11 ] All our cases had cystic contents, while one had an accompanying hernia. Magnetic resonance imaging (MRI) is used when USG is inconclusive, providing additional information about herniated structures and their anatomical relationship with intraperitoneal structures. The canal of Nuck hydrocele appears hypointense on T1-weighted images and hyperintense on T2-weighted images. Faint internal septation may be observed in cases complicated by infection or inflammation. MRI is often used to rule out other potential differential diagnoses [ 10 , 12 ]. Differential diagnoses of cystic inguinolabial swelling in females include indirect inguinal hernia or femoral hernia, Bartholin's cyst, lipoma, vascular aneurysms, and rarely, cystic lymphangiomas, leiomyomas, sarcomas, endometriosis of the round ligament, or epidermal cysts [ 7 , 13 ]. Surgery is the treatment of choice for all hydroceles involving the canal of Nuck, as there is an increased incidence of associated complications such as infection and bleeding. [ 12 , 13 ] Surgery was also performed to confirm the diagnosis. The surgical procedure involves resection of the hydrocele, ligation of the neck of the processus vaginalis, and repair of any associated hernia, if present. [ 2 , 14 ] The choice between an open or laparoscopic approach for surgery depends on the surgeon's expertise and familiarity and the availability of resources at the institution. [ 15 ] Complications related to hydrocele can include infection or rupture and strangulation of the associated inguinal hernia. Complications related to surgery may include infection, recurrence, and complications due to damage to the local lymphatic system. [ 12 , 16 ] None of the patients experienced any complications and had an uneventful recovery.

Not commissioned, externally peer reviewed.

During the embryological development of a female fetus, the round ligament of the uterus descends to the ipsilateral labia majora through the inguinal canal. [ 1 ] Accompanying the round ligament is a peritoneal fold, known as the canal of Nuck in females, named after Anton Nuck, the Dutch anatomist who first described it. Typically, the canal of Nuck undergoes obliteration during the first year of life. Failure to achieve complete obliteration can result in the development of an indirect inguinal hernia or hydrocele in the Canal of Nuck. [ 1 , 2 ] Hydrocele of the canal of Nuck is a rare clinical condition that mainly presents with painless labial swelling and is often underrecognized and frequently misdiagnosed despite its potential for severe morbidity. [ 3 , 4 ] In this case series, we report five cases of the canal of Nuck hydrocele managed at our center, highlighting the need to consider it as a differential diagnosis in young females with inguinolabial swellings. In all cases, prompt ultrasound evaluation can differentiate the presence of a canal of Nuck abnormality and determine the nature of the contents, aiding in deciding surgical management. This case series has been reported in line with the PROCESS Guideline. [ 5 ]

We prospectively collected the data of female patients diagnosed with hydrocele of the canal of Nuck from patients admitted to our general surgery department over two years (2021 and 2022). They were all aged between one year and six years. None of them had any past comorbidities or any history of surgery. All patients presented with painless swelling in the unilateral or bilateral inguinal region. Their parents noted the swelling, and the duration of symptoms varied from three months to two years. There were no complaints of abdominal pain, abdominal distension, vomiting, or systemic symptoms. The clinical examination revealed well-defined pear-shaped swelling in the inguino-labial region unilaterally in four cases (three right and one left-sided) and bilaterally in one case. The swellings were irreducible, fluctuant, and had normal overlying skin. There was no tenderness and no expansive impulses. The other examination findings were unremarkable. Complete blood count and urinalysis results were within normal limits in all cases. Surgical management was done in all patients with careful dissection of the cyst from the round ligament followed by ligation of the canal of Nuck near the deep inguinal ring (See Fig. 1 ). The wound was closed in layers. The associated hernia in case #2 was corrected by herniotomy. All patients had an uneventful postoperative course without any recorded postoperative wound infection or recurrence. All the demographic and clinical details are tabulated in Table 1 . Fig. 1 Intraoperative inguinal exploration of case #1 revealed a canal of Nuck hydrocele. Fig. 1 Table 1 Demographics and clinical presentation of the five cases. Table 1 Case # Age Duration of symptoms Size (mm) Side Associated Hernia 1 1 year 6 months 11 × 10 Right None 2 4.5 years 1 year 17 × 10 Right Right indirect inguinal 3 1 year 3 months 15 × 10 Left None 4 6 years 2 years 27 × 8 Right None 5 2 years 6 months 13 × 8 and 22 × 10 Bilateral None Intraoperative inguinal exploration of case #1 revealed a canal of Nuck hydrocele. Demographics and clinical presentation of the five cases.

All the authors certify that they have no competing interests to declare that are relevant to the content of this article.