A 3-month-old boy is brought to the physician because his parents cannot find one of his testicles. Physical examination confirms the parents’ observation. The patient develops a urogenital tumor 30 years later. An abdominal-pelvic CT scan reveals metastases to lumbar periaortic lymph nodes. Which of the following is the most likely pathologic diagnosis?
**Core Concept**
The clinical presentation of a missing testicle at birth, followed by the development of a urogenital tumor and metastases to lumbar periaortic lymph nodes, suggests a case of testicular cancer with a possible genetic link. This scenario is associated with a condition where the testicle fails to descend into the scrotum during fetal development.
**Why the Correct Answer is Right**
The most likely diagnosis in this scenario is a type of testicular cancer known as **nonseminomatous germ cell tumor (NSGCT)**. NSGCTs are a type of testicular cancer that arise from germ cells and can be associated with cryptorchidism (undescended testes). The tumor in this case developed 30 years after the initial presentation, suggesting a possible genetic predisposition. The metastases to lumbar periaortic lymph nodes are characteristic of testicular cancer, as these lymph nodes are part of the primary drainage pathway for the testes.
**Why Each Wrong Option is Incorrect**
**Option A:** **Seminoma** is a type of testicular cancer, but it is more commonly associated with a better prognosis and a higher likelihood of responding to radiation therapy. The clinical presentation in this case is more suggestive of NSGCT.
**Option B:** **Yolk sac tumor** is a type of NSGCT, but it is more commonly seen in children and is often associated with a worse prognosis. While it is a possible diagnosis, the clinical presentation in this case suggests a more differentiated tumor.
**Option C:** **Rhabdomyosarcoma** is a type of soft tissue sarcoma that can occur in the testes, but it is much less common than testicular cancer and is not typically associated with cryptorchidism.
**Option D:** **Leydig cell tumor** is a type of sex cord-stromal tumor that can occur in the testes, but it is not typically associated with cryptorchidism or the development of metastases to lumbar periaortic lymph nodes.
**Clinical Pearl / High-Yield Fact**
The association between cryptorchidism and testicular cancer is well established, with men who have a history of undescended testes having a 3- to 10-fold increased risk of developing testicular cancer. This is thought to be due to the abnormal environment in the abdominal cavity, which may promote the development of malignant germ cells.
**Correct Answer:** C. **Nonseminomatous germ cell tumor (NSGCT)**