AssessmentsTesticular and scrotal conditions: Pathology review
USMLE® Step 1 style questions USMLE
A 31-year-old man comes to his primary care physician after feeling a lump on his right testicle. The patient denies any associated pain. He has no significant past medical history. Vitals are within normal limits. Physical examination reveals a mobile, soft, round mass superior and posterior to the right testis. The nodule transilluminates when a penlight is held behind it. An ultrasound of the mass is performed and demonstrates posterior acoustic enhancement. Which of the following is the most likely anatomic location of this patient’s condition?
Content Reviewers:Antonella Melani, MD
In the middle of the night, a 16 year old male named Shane is brought to the emergency department by his parents after waking up with severe pain in his right scrotum. Shane does not recall any traumatic events prior to the onset of his symptoms. On physical examination, the scrotum appears swollen; in addition, you notice that the pain is worsened with elevation of the scrotum, and stroking of the right inner thigh does not result in elevation of the right testis.
Later that day, you meet a 28 year old male called Elias, who comes in for a fertility evaluation. Elias and his wife have been trying to conceive for two years without success. Recently, Elias has also noticed an enlargement and a feeling of pressure in his left scrotum. On physical examination, you palpate a mass along the spermatic cord that feels like a “bag of worms”.
Based on the initial presentation, both Shane and Elias seem to have some form of testicular and scrotal condition. Now, for your exams, remember that the testes begin their development in the abdominal cavity, within the peritoneum. During the third trimester of pregnancy, the testes usually begin to descend into the pelvis via the inguinal canal, and ultimately settle in the scrotum. This needs to occur because sperm can't survive at body temperature, and that’s a high yield fact!
Now, as the testes gradually migrate, a peritoneal outpouching called the processus vaginalis forms, and pulls the layers of the anterolateral abdominal wall with it into the developing scrotum. The testes then follow the processus vaginalis into the scrotum. After the testes have descended to the scrotum, the processus vaginalis closes up. Within the scrotum, each testis remains partially covered by an extension of the peritoneum, which forms a serous layer called the tunica vaginalis. The only part that’s not covered by the tunica vaginalis is where the testes are attached to the epididymis and spermatic cord.
Now, the epididymis is a coiled tube located at the back of the testicles, and moves the sperm from the testicles into the vas deferens, which in turn transports the sperm to the urethra. On the other hand, the spermatic cord is the structure that contains the vas deferens, and also carries a network of arteries, veins, lymphatics, and nerves to the testicles.
Let’s start with epididymitis, which is an inflammation of the epididymis. What’s important to remember is that in individuals younger than 35 years old, epididymitis is most commonly associated with sexually transmitted organisms, such as Chlamydia trachomatis and, less commonly, Neisseria gonorrhoeae. On the other hand, in individuals older than 35 years, the most common organisms causing epididymitis are gram-negative bacteria, predominantly Escherichia coli, as well as Pseudomonas aeruginosa; and it’s often associated with urinary tract infections or benign prostatic hyperplasia.
Now, the main symptom of epididymitis is acute onset scrotal pain, which might also be accompanied by fevers, chills, and myalgias or muscle pain. The diagnosis of epididymitis primarily relies on physical examination, revealing tenderness and swelling of the posterior side of the affected testicle. For your exams, remember that a telltale sign of epididymitis is a positive Prehn sign, meaning that the pain is relieved when elevating the testicle.
In addition, individuals with epididymitis typically present with an intact cremasteric reflex, so lightly stroking or poking the superior and inner part of the thigh elicits a contraction of the cremaster muscle, causing the testis to elevate ipsilaterally. To confirm the diagnosis, urinalysis, urine culture, and a urine nucleic acid amplification test for Neisseria gonorrhoeae and Chlamydia trachomatis should be performed. Treatment includes antibiotics.
Now, in some cases, epididymitis can spread to the testicle, resulting in epididymo-orchitis. Isolated orchitis, or inflammation of the testis, is rare; for your exams, remember that it is classically associated with mumps infection. Symptoms of orchitis include acute onset scrotal pain, along with fever, nausea, and vomiting. For diagnosis, physical examination shows testicular swelling and tenderness, with a positive Prehn sign and normal cremasteric reflexes. Treatment is mainly supportive.
Now, another high yield cause of acute onset scrotal pain is testicular torsion. In fact, keep in mind that testicular torsion is one of the most common causes of acute scrotal pain among individuals between the ages of 12 and 18 years old. Now, testicular torsion occurs when the testes twist around the spermatic cord, basically cutting off its blood supply. This can happen either spontaneously or after trauma or vigorous physical activity. Individuals typically present with acute and severe scrotal pain, often accompanied by nausea, vomiting, and diffuse lower abdominal pain.
Diagnosis of testicular torsion is mainly based on physical examination, where there’s a tender, enlarged, high-riding testis, with its long axis oriented transversely due to the shortening of the spermatic cord. This is called a bell clapper deformity and it’s extremely high yield!
Another characteristic finding of testicular torsion is a negative Prehn sign, so when elevating the scrotum, the pain isn’t relieved, and actually gets worse. Another thing to bear in mind is that the cremasteric reflex is absent in testicular torsion, so stroking or poking the superior and inner part of the thigh does not result in elevation of the testis. So, in a test question monitoring acute onset scrotal pain, watch out for these two findings, which should help you differentiate testicular torsion from epididymitis and orchitis. Finally, diagnosis of testicular torsion can be confirmed with a doppler ultrasound.
Treatment involves surgical correction by performing an orchidopexy, which is basically fixing the affected testicle into the afferent scrotum, and should be done within 6 hours from the onset of symptoms. If the surgery cannot be performed within that time frame, a manual detorsion of the testicle can be done. Keep in mind that delayed treatment can cause testicular nonviability and infertility, in which case the surgical removal of the affected testicle, or an orchiectomy, is needed.
Our next condition is cryptorchidism, which is the most common birth defect in biological males. Cryptorchidism occurs when one or both of the testicles fail to descend into the scrotum, and often get stuck in the inguinal canal. For your exams, note that this most commonly affects premature babies. Now, the real problem here is that the undescended testes will remain at body temperature, which impairs spermatogenesis, leading to fertility issues.
Now, high temperatures also affect Sertoli cells, which normally secrete testosterone in response to follicle stimulating hormone or FSH. In contrast, high temperatures may not affect Leydig cells as much, so they’re able to secrete testosterone in response to luteinizing hormone or LH. As a result, individuals with cryptorchidism can have normal levels of testosterone, especially when it’s unilateral, while testosterone levels are typically decreased in case of bilateral cryptorchidism. And that’s very high yield!