Testicular Disorders & Cancer

Cryptorchidism is characterized by the failure of one or both testicles to descend fully into the scrotum. Cryptorchidism is more prevalent in premature infants, and is usually detected through inguinal fullness or a palpable mass and is. The inguinal canal is the most frequent site of undescended testes. While often an isolated occurrence, bilateral cryptorchidism may signal an underlying genetic disorder, notably Klinefelter syndrome, which also presents with hypogonadism. Klinefelter syndrome elevates the risk of testicular cancer and infertility, largely due to the higher abdominal temperatures that lead to atrophy of the Sertoli cells and seminiferous tubules. The standard treatment is surgical orchiopexy, aimed at lowering the testis to mitigate these risks.

Varicocele is marked by the dilation of the pampiniform plexus. The anatomical configuration where the left renal vein and the left gonadal (testicular) vein join at a 90-degree angle contributes to inefficient venous drainage on the left side. This suboptimal drainage is further aggravated by the compressive force exerted by the superior mesenteric artery. Varicocele usually presents as a dull, aching scrotal pain that is exacerbated when standing and relieved in a supine position. Chronic varicocele can contribute to testicular atrophy and infertility if untreated.

Testicular torsion is a urological emergency that occurs when the testis is twisted around its spermatic cord—often stemming from a congenital defect that results in inadequate fixation to the tunica vaginalis. The twisting leads to venous compression, subsequently causing testicular edema and arterial occlusion. Testicular torsion manifests as sudden, severe scrotal pain, often accompanied by nausea, vomiting, and a loss of the cremasteric reflex. Immediate surgical intervention is required to prevent testicular infarction.

Hydrocele manifests as painless swelling of the scrotum due to serous fluid accumulation within the tunica vaginalis. It comes in two forms: communicating hydrocele, which is congenital and arises from an incompletely obliterated processus vaginalis, and noncommunicating, which is usually acquired following conditions such as epididymitis, trauma, or torsion. Transillumination can distinguish hydroceles from other conditions like varicocele and tumors.

Testicular cancer represents the most common malignancy in males between the ages of 15-35. Testicular cancer is predominantly comprised of germ cell tumors, which are further categorized into seminomas and non-seminomas.

Seminomas are the most common testicular tumors and are histologically identical to dysgerminomas of the ovary. They typically present with homogenous testicular enlargement, as opposed to an isolated mass. Histologically, these tumors exhibit a "fried egg" appearance, also a characteristic of ovarian dysgerminomas. The tumor markers for seminomas include β-hCG and lactate dehydrogenase (LDH).

Non-seminomas are a diverse group that includes yolk sac tumors, teratomas, embryonal carcinomas, and choriocarcinomas.

Yolk sac tumors are most commonly seen in boys under 3 years old and are similar to ovarian yolk sac tumors. Histologically, they contain Schiller-Duval bodies, which are papillary structures with a central vessel. α-fetoprotein (AFP) serves as the tumor marker. Teratomas in the testicles can be either benign or malignant, in contrast to their ovarian counterparts, which are always benign. Mature teratomas contain cells from all three germ layers and often include components like hair and teeth, whereas immature teratomas contain poorly differentiated tissues and are malignant. Embryonal carcinomas are far more common in the testes compared to the ovaries and manifest as hemorrhagic masses with areas of necrosis. They show sheets of atypical, poorly differentiated cells upon histological examination. β-hCG is also a tumor marker for this type. Choriocarcinomas are highly aggressive tumors that spread hematogenously, often metastasizing to the lung or brain by the time of diagnosis. These tumors contain disordered proliferations of both mononuclear cytotrophoblasts and multinucleated syncytiotrophoblasts. Choriocarcinomas are characterized by extremely high levels of β-hCG, which can present with hyperthyroidism due to hCG's affinity for the TSH receptor, or with gynecomastia due to Leydig cell dysfunction and increased estrogen production.