Summary Points

-The testes have two main functions of spermatogenesis, or production of sperm (an endocrine function), and androgens male (hormonal secretion), its exocrine function.

-Trauma to the testis that may cause torsion is important because ischemia of only 1-3 hours, for example, results in decreased spermatogenesis and irreversible changes occur in only 6-8 hours.

-Testicular cancer is the most commonly occurring malignancy in men between the ages of 15 and 35. The incidence for mixed germ cell tumors alone is two to three cases per 100,000 males per year. Testicular cancer makes up about 1 percent of all cancers in men in the United States.

-The male reproductive system develops embryonically under the influence of the “Y” chromosome, testosterone, and female inhibitory substances. The mesonephric ducts (also called wolffian ducts), which is the male duct system, and the paramesonephric, ducts (also called mullerian ducts) that form the female reproductive ducts. So the newly developing testes produce testosterone to promote mesonephric duct development or the male genitalia, and suppress the mesonephric ducts (also called wolffian ducts), which is the male duct system, and the paramesonephric, ducts (also called mullerian ducts) that form the female reproductive ducts. So the newly developing testes produce testosterone to promote mesonephric duct development or the male reproductive system, and suppress paramesonephric development, which feminizes the reproduction systems development, which feminizes the reproduction system.

-Each embryonic testis must descend from its posterior abdomen location through the inguinal canals located in the anterior abdomen. The testes begin their migration to the scrotum at about the twenty-eighth week lasting 2 or 3 days. About week 32 the testes are fully descended into the scrotum in 97 percent of males and shortly after birth for the remainder three percent. For the 3 percent of full-term males who may have an undescended testis the testis should complete migration in the first year post gestation. Cryptorchidism, the medical term for undescended testis, is a pathological condition in newborns and requires medical or surgical attention when it persists.

-The risk of malignant testicular tumor with cryptorchidism is 10 to 40 times normal descended testes. The higher in the abdomen the testis the greater the risk, and if both are undescended versus only one undescended.

-The epididymides are paired organs described as a “comma-shaped” structure along the superior and posterolateral surface of each testicle. Named parts of the epididymis are the head, body, and tail.

-The process involves reduction division of the human gene complement by a process called meiosis. Meiosis is a very efficient process producing thousands of sperm each second in healthy males. More than 100 million sperm are produced each day in normal fertile testes. From the beginning of meiosis to full maturation is about 2 month.

-Knowing the normal texture of the testes is important to the sonographer. The normal testis appears homogenous on ultrasound with an echo texture similar to the thyroid gland. The normal testis appears encapsulated owing this presentation to a hypoechoic ring, which is the tunica vaginalis.

-Structures to be demonstrated are: the mediastinum of the testis, rete testis, head of the epididymis (body and tail with hydrocele), and testis. The mediastinum of the testis is often seen as an echogenic linear band with longitudinal imaging of the testicle. The rete testis is visualized as a hypoechoic or septated cystic area near the head of the epididymis.

-The epididymis is distinguished from the testicle by it being isoechoic or slightly more echogenic than the testis. The echotexture looks coarse compared to the adjacent testis.

-Doppler imaging with ultrasound is a technique for demonstrating the blood flow to the testis and epididymis. Maximum effectiveness of Doppler imaging of the testis for ischemia is achieved when images are acquired at early suspicion of ischemia. The effectiveness diminishes as reactive scrotal inflammation occurs in conditions like torsion.

-Color Doppler (CD) is an imaging technique that allows the sonographer to demonstrate blood flow images in color placed over real time B-mode images. Red is allocated for flow towards the transducer and blue is allocated for blood flow away from the transducer. To measure what type of vessel is being demonstrated pulsed wave Doppler (PWD) can be used.

-Pulsed wave Doppler technique can be used to determine whether a vessel is arterial or venous by observing the waveform pattern shows the signal as being either above or below baseline. High resistance shows high systolic peak and low diastolic flow. Low resistance shows a double or biphasic systolic flow and high diastolic flow.

-It is important for the sonographer to know the appearance of a normal Doppler waveform for blood flow to the testicles. The normal arterial Doppler waveform will have a low-impedance for the testicular artery, and a large amount of end diastolic flow within the artery. The diferential and cremasteric arteries are found within the spermatic cord, and should show a high resistance waveform and an absence of diastolic flow.

-Blood flow in the testicular artery is low resistance. Blood flow in the cremasteric artery is high resistance, and flow in the diferential artery is high resistance.

-A hydrocele is a collection of fluid in the tunica vaginalis. It is a common cause of painless scrotal enlargement. A pyelocele is pus in the tunica vaginalis. Blood and pus within the scrotal sac is frequently accompanied with pain. A collection of lymphatic fluid in the tunica vaginalis is a chylocele.

-A varicocele is caused when veins within the spermatic cord becomes excessively dilated resulting in a cystic-like varix. The primary cause is incompetent valves of the pampiniform plexus, but can also result from a blockage of the testicular veins or renal veins. Patients often describe their situation as having two testicles on one side. This condition most commonly affects the left testicle approximately 80% of the time.

-Varicocele can be demonstrated with color Doppler; however, the sonographer must have the patient perform the “Valsalva technique,” which involves suspended inspiration is used to temporary increase venous pressure.

-Epididymitis is the inflammation of the epididymis and is the most common cause of acute scrotal pain. Acute epididymitis appears hypoechoic on ultrasound, and Doppler shows increased blood flow. Chronic epididymitis presents differently, it shows enlargement and areas that are affected will be hyperechoic.

-Orchitis is inflammation of the testes usually related to and secondary to epididymitis. It commonly occurs because of an infection in the urinary tract (cystitis, urethritis, and genitoprostatitis) that seeds to the epididymis and testis through the lymphatics or ductus deferens. It also can result from mumps, trauma or autoimmune reaction.

-Testicular microlithiasis (TM) is seen on approximately 0.6% of testicular sonograms. Microlithiasis describes calcifications found inside the seminiferous tubules or testicles and is a very uncommon condition. Ultrasound shows several, small hyperechoic foci scattered through out the testicle. These tiny punctate echogenic foci may be easy to recognize because they do not typically shadow. Microlithiasis has been associated with testicular cancer so those patients with this condition should be watched closely.

-Testicular tumors characteristically spread through lymphatic channels first affecting retroperitoneal and para-aortic nodes. From retroperitoneal nodes it spreads to the mediastinal and subclavicular nodes. When hematogenous spread occurs the lungs are the primary organs affected. Secondary hematogenous spread may involve the liver, brain or bone.

-The main difference between seminoma and NSGCT is that seminomas tend to stay localized to the testis. Because the stay localized for a long time over 70% are discovered while still within the testis. Seminomas are highly radiosensitive accounting for a high cure rate of 85-95%.

-Certain serum tumor markers are elevated when there is a testicular tumor. This is because certain germ cell tumors secrete hormones and specific enzymes detectable by laboratory tests. Some of these bio-molecular markers include: human chorionic gonadotropin (HCG), alpha fetal protein (AFP), lactic dehydrogenase, placental lactogen, and placental alkaline phosphatase. The two most reliable ones are AFP and Beta-HGC.

-Choriocarcinoma is another type of neoplasm that occurs in males 20-30 years of age. It is the least common type of neoplasm accounting for 1-3% of germ cell tumors. However, it is the most malignant of testicular cancers killing almost all its victims within five years of diagnosis.

-Teratomas comprise about 10-15% of germ cell tumors. They are composed of all three germ layers, the mesoderm, ectoderm, and endoderm tissues. About a third of teratomas of the testicle will metastasize through lymphatic spread within 5 years of discovery.

-About 40% of testicular tumors are mixed; the most common mix is teratoma and embryonal carcinoma. Alpha-Fetoprotein is raised when embryonal carcinoma is present, and beta-HCG is found in over 50% of nonseminomatous tumors and some pure seminomas.


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