Hydrocele: A common condition in infants where fluid accumulates around a testicle, causing the scrotum to swell. It's often due to a patent processus vaginalis, which is a communication between the abdominal cavity and the scrotum.

Inguinal Hernia: Similar to a hydrocele, an inguinal hernia occurs when part of the intestine protrudes through a weak spot in the abdominal muscles, which can also cause a scrotal mass.
Testicular Torsion: Although less common, testicular torsion is a condition where the spermatic cord becomes twisted, cutting off the blood supply to the testicle. It's a medical emergency but can present as a scrotal mass.
Epididymitis: Inflammation of the epididymis, which can cause pain and swelling in the scrotum, is another possible diagnosis, though less common in infants.

Testicular Tumor: Although rare in infants, testicular tumors can present as a scrotal mass. Early detection is crucial for effective treatment.
Trauma: Physical trauma to the scrotum can cause a hematoma or other injuries that might be mistaken for other conditions. It's essential to consider the history of the infant.

Varicocele: An enlargement of the veins within the scrotum, which is uncommon in infants but can cause a scrotal mass.
Spermatocele: A cystic structure that contains sperm, usually found near the head of the epididymis, which is rare in infants.
Scrotal Teratoma: A rare type of tumor that can occur in the scrotum, containing several different types of tissues.