A 20-year-old male presents with a mass in the groin. On inspection with the patient standing a symmetric, round swelling is noted at the external ring. When the patient lies down the mass disappears. The most likely diagnosis is

• A. Indirect inguinal hernia
• B. Obturator hernia
• C. Femoral hernia
• D. Direct inguinal hernia

Answer: (D)

Inguinal hernias present as a reducible groin mass that often appears with standing and disappears when the patient lies down. The key distinction is how the hernia exits the abdomen: indirect inguinal hernias pass through the deep inguinal ring and then through the superficial ring into the inguinal canal, typically lateral to the inferior epigastric vessels, and they commonly extend into the scrotum. This pattern fits a young male with a mass located at the external ring that is reducible with recumbency, since the persistent processus vaginalis allows abdominal contents to protrude through the canal.

Direct inguinal hernias, in contrast, arise from weakness of the posterior wall (Hesselbach’s triangle) and push medially to the inferior epigastric vessels; they are more common in older men and rarely extend into the scrotum. Obturator and femoral hernias have distinct clinical presentations and demographics (obturator often presents with thigh pain, and femoral hernias typically occur below the inguinal ligament, more common in women).

So the presentation is most consistent with an indirect inguinal hernia: a reducible groin mass near the external ring in a young patient, due to a patent processus vaginalis allowing the hernia to track through the inguinal canal.