Differential Diagnosis for Right Testicular Pain with Normal CT Scan and Ultrasound

Single Most Likely Diagnosis

• Epididymitis: This is an inflammation of the epididymis, a tube at the back of the testicle that stores and carries sperm. It's a common cause of testicular pain and can be caused by bacterial or viral infections. The fact that CT and ultrasound are normal doesn't rule out epididymitis, as these imaging modalities may not always detect inflammation of the epididymis.

Other Likely Diagnoses

• Orchitis: Inflammation of one or both testicles, usually caused by bacterial or viral infections. Like epididymitis, orchitis might not be visible on CT or ultrasound, especially in early stages.
• Testicular torsion (early stages): Although less likely if the ultrasound is normal, early stages of testicular torsion might not show characteristic findings on imaging. Clinical suspicion remains crucial.
• Varicocele: An enlargement of the veins within the scrotum, similar to varicose veins. While often asymptomatic, a varicocele can cause a dull ache.

Do Not Miss Diagnoses

• Testicular Torsion: Despite the normal ultrasound, testicular torsion is a medical emergency that requires prompt surgical intervention to save the testicle. It can sometimes present with normal imaging if the torsion is intermittent or if the imaging is done after the testicle has untorsed.
• Appendix Testis Torsion (Hydatid of Morgagni): A small appendage at the top of the testicle can twist and cause severe pain. This condition is less common but can mimic testicular torsion in presentation.
• Acute Segmental Testicular Infarction: A condition where a portion of the testicle loses its blood supply, leading to infarction. It can present with acute testicular pain and might have a normal ultrasound if the infarction is small or in early stages.

Rare Diagnoses

• Spermatocele: A cystic structure filled with sperm that arises from the head of the epididymis. It's usually asymptomatic but can cause discomfort or pain if large enough.
• Cystic dysplasia of the testis: A rare congenital anomaly that can cause testicular pain due to cystic changes within the testicle.
• Testicular cancer: While testicular cancer can cause a painless testicular mass, some patients may experience pain, especially if the tumor causes bleeding or invasion into surrounding structures. However, this would be less likely with normal imaging.