Pathophysiology of the Canal of Nuck
- Extension of the parietal peritoneum follows the round ligament as it passes to the inguinal canal.
- Usually gets obliterated.
- This evagination of the parietal peritoneum = the canal of Nuck = female counterpart of processus vaginalis in men.
- If it is:
- Completely patent: Avenue for an indirect inguinal hernia and hydrocele (Canal of Nuck hernia).
- Obliterated at the level of both the superficial and deep inguinal rings: Fluid may be trapped in between both ends of the canal, creating a Canal of Nuck cyst.
- Obliterated at lower end – Infantile hydrocele / encysted hydrocele.
- Hydrocele vs cyst canal of Nuck : The terms hydrocele and cyst of Canal of Nuck are used interchangeably but these are separate pathologies.
- Symptoms: It usually presents as a painless swelling in the inguinal region. Infection can cause pain.
Imaging appearances:
- Canal of Nuck cyst is an inguinal cyst in females.
- US : Cystic lesion in the inguinal canal with posterior acoustic attenuation.
- CT : Hypodense lesion with our without internal septations.
- MRI: T1 isointense, T2 hyperintense, typical appearance of a cystic lesion.
- Can show peripheral enhancement.
Differentials for Canal of Nuck cyst
- Inguinal hernia containing fluid in patients with ascites.
- Soft tissue tumor.
- Endometriosis cyst
- Cyst
- Abscess
- Lymphadenopathy
Management:
Surgical excision or conservative management depending on patient presentation.
Detailed video with PACS based case images:
