The advanced practice registered nurse (APRN) is assessing a 17 year-old patient who presents with complaints of a nontender mass in the right scrotum, which "comes and goes" per patient report. During the physical exam of the genitalia, the APRN asks the patient to "cough". While the patient coughs, the APRN uses their index finger to assess the inguinal canal and notes a bulge touching the finger during coughing. What is the most likely cause of the mass?