Diagnosis: Varicocele
Based on the clinical presentation of dull testicular ache over several days, fullness of the left scrotal sac, palpable dilation of the spermatic cord, and absence of transillumination, the most likely diagnosis is varicocele.
Key Diagnostic Features Supporting Varicocele
The clinical presentation contains several pathognomonic features:
Dull, chronic pain pattern over multiple days rather than acute severe onset distinguishes this from testicular torsion, which presents with abrupt, severe scrotal pain 1
Palpable dilation of the spermatic cord is the hallmark physical finding of varicocele, representing dilated veins of the pampiniform plexus
Left-sided predominance is characteristic, as varicoceles occur more commonly on the left side due to anatomical differences in venous drainage
Absence of transillumination helps exclude hydrocele, which would demonstrate fluid transmission of light 2
Ruling Out Alternative Diagnoses
Testicular Torsion - Excluded
- Torsion presents with abrupt onset of severe scrotal pain, not dull ache over days 1, 3
- The patient would typically be in distress with nausea and vomiting 1, 4
- Physical examination would show an absent cremasteric reflex, abnormal testicular position (high-riding), and severe tenderness 4
- Time course is critical: torsion requires surgical intervention within 6-8 hours to prevent testicular loss 1, 3
Epididymitis - Less Likely
- While epididymitis is the most common cause of acute scrotal pain in adults and adolescents 2, 1, this patient lacks key features
- Epididymitis typically presents with gradual onset but still involves more acute pain than described here 1
- The patient denies dysuria, urethral discharge, and is not sexually active 1
- Physical examination would show an enlarged, tender epididymis with increased blood flow on Doppler 2, 1
Inguinal Hernia - Excluded
- Hernias typically present with reducible masses that may extend into the scrotum
- The clinical description of "dilation of the spermatic cord" is more consistent with vascular engorgement than bowel contents
- Hernias would not produce the specific finding of cord dilation described
Testicular Cancer - Less Likely
- While testicular masses can present with dull ache, the specific finding of spermatic cord dilation points away from this diagnosis
- Testicular cancer typically presents as a painless testicular mass rather than cord abnormalities
- The patient's age makes cancer less likely than varicocele
Clinical Pitfalls to Avoid
- Never dismiss acute scrotal pain without excluding torsion first - even with a chronic presentation, intermittent torsion remains possible 1
- The absence of severe pain and normal vital signs make torsion unlikely, but if any doubt exists, urgent Doppler ultrasound should be performed 2, 1
- In prepubertal boys, torsion of testicular appendage would be more common and can present with the "blue dot sign," but this patient's age and cord dilation findings make varicocele more likely 1, 5