Differential Diagnosis for a 21-year-old man with a hard nontender 5 mm nodule on the anterior surface of the left testicle
- Single most likely diagnosis:
- Testicular cancer (specifically, a testicular tumor such as seminoma or non-seminoma): The presentation of a hard, nontender nodule on the testicle is highly suggestive of testicular cancer, which is the most common malignancy in young men.
- Other Likely diagnoses:
- Epididymal cyst or spermatocele: These are benign cysts that can present as hard, nontender nodules on the testicle, although they are more commonly found on the posterior surface.
- Varicocele: A varicocele is an enlargement of the veins within the scrotum and can present as a nontender "bag of worms" on the testicle, but it's less likely to be described as a hard nodule.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Testicular torsion (although this typically presents acutely with severe pain): While the patient's nodule is described as nontender, any testicular complaint warrants consideration of torsion due to its emergency nature.
- Metastatic disease: Although rare, metastases to the testis from other primary cancers can occur, and a new testicular nodule in a young man could potentially be a sign of an underlying malignancy elsewhere.
- Rare diagnoses:
- Adrenal rest tumors: These are rare, benign tumors that can occur in the testes of individuals with congenital adrenal hyperplasia.
- Granulomatous orchitis: This is an inflammatory condition of the testis that can cause nodules, but it's less common and typically associated with other symptoms such as pain or systemic illness.
Justification for the options provided in the question:
- Crytorchidism (undescended testes) is a risk factor for testicular cancer but does not directly explain the nodule.
- Hydrocele is an accumulation of fluid around a testicle that would not typically present as a hard nodule.
- Testicular trauma could potentially lead to a nodule if there was a hematoma, but the history provided does not mention trauma.
- Orchitis (inflammation of the testis) is usually associated with pain and swelling, not a hard, nontender nodule.