Review Question - QID 109770

A 10-year-old boy presents to his pediatrician for a well-child appointment. The patient has been doing well in school. He plays on a club basketball team and is also a member of the chess club. He has many friends and is happy. His parents have no concerns. His temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 85/min, respirations are 17/min, and oxygen saturation is 98% on room air. On physical exam, the patient is noted to be a tall, muscular young boy. He is in the 99th percentile for weight and height. Cardiopulmonary exam is within normal limits. The patient's abdomen is obese, non-tender, and non-distended. Neurological exam is grossly non-focal. Testicular exam is notable for a right-sided testicular mass that appears to be fixed. Musculoskeletal exam reveals a normal range of motion and 5/5 strength in his upper and lower extremities. Dermatologic exam reveals acne and facial hair on the patient's face. Which of the following is the most likely underlying diagnosis?