The deceptive groin mass: encysted hydrocele of the canal of Nuck mimicking an inguinal hernia in an adult female

Abstract

An encysted hydrocele of the canal of Nuck is a rare developmental anomaly in adult females, resulting from the incomplete obliteration of the processus vaginalis. It frequently mimics an inguinal hernia, leading to diagnostic challenges. We present the case of a 38-year-old female who presented with a right inguinal swelling present for five months. The patient exhibited a reducible right groin swelling that became prominent on straining, initially diagnosed clinically as a right inguinal hernia. Magnetic resonance imaging (MRI) demonstrated a 10-mm defect in the right inguinal region with an adjacent 18×10 mm cystic lesion. The patient underwent an open surgical exploration under spinal anesthesia. Intraoperatively, a well-defined cystic swelling containing clear fluid was identified along the round ligament, with no indirect hernia sac or peritoneal communication. The sac was completely excised, and the weakened posterior wall was reinforced using a 6×11 cm polypropylene mesh. Histopathological examination confirmed fragments of fibrocollagenous to muscular tissue with chronic inflammatory cells, consistent with a hydrocele sac. The patient had an uneventful postoperative recovery. The canal of Nuck hydrocele is a rare embryological relic that acts as a diagnostic chameleon in adult females, easily masquerading as a standard inguinal hernia. Definitive management requires a high index of intraoperative suspicion, complete surgical excision of the cyst, and concurrent prosthetic reinforcement of the frequently attenuated inguinal floor to ensure recurrence-free recovery.