Going Against the Grain: A Case Report of an Endometriosis in the Canal of Nuck

The canal of Nuck is an embryological remnant of the processus vaginalis found in females, and is a potential site for endometriosis seeding. Endometriosis in the canal of Nuck is an exceedingly rare condition. Patients with this condition present with groin swelling or suprapubic pain. We describe a case of a 44-year-old female presenting for left inguinal pain and a lump. Physical examination revealed a 3 cm reducible mass; magnetic resonance imaging (MRI) revealed a 6.2 × 3.0 × 1.7 cm multiloculated cystic structure, extending from the left pelvic region into the left inguinal region near the round ligament. The patient underwent surgical excision of the mass. Pathology revealed a multi-cystic lesion lined with mesothelium cells and a fibrous wall with multiple foci of misplaced endometrial glands and stroma, corroborating a diagnosis of endometriosis in the canal of Nuck.

Learning points: Endometriosis of the canal of Nuck is an exceedingly rare entity with an uncertain pathophysiology due to paucity of data available in the medical literature.Physicians should keep Nuck's canal endometriosis in their differential diagnosis when approaching a patient with chronic pelvic pain.