Lecture 1 superficial structures SCROTUM Holdorf Lecture 1 superficial structures SCROTUM

SCROTUM Testicular abscess   Scrotal calcifications Normal anatomy Testicular infarct Malignant testicular tumors Hydrocele Varicocele Seminoma Scrotal hernia Pre-pubertal testicular tumors Extratesticular tumors Spermatoceles (Epididymal cysts) Teratomas Laboratory values The acute scrotum Choriocarcinoma Epididymitis Mixed germ cell tumors Testicular torsion Testicular Metastases Cryptorchidism Testicular cysts Epidermoid cysts

SCROTUM OUTLINE Normal Anatomy The normal testis has a homogeneous medium-level echo texture. The testicle is surrounded by a fibrous capsule, the tunica albuginea. Multiple septations (septula) arise from the tunica albuginea to form the mediastinum testis, which is sonographically seen as an echogenic linear band extending longitudinally within the testis.   The septula forms wedge-shaped compartments that contain the seminiferous tubules. The seminiferous tubules converge to form the tubuli recti. The tubuli recti enter the mediastinum testis forming a network of channels called the rete testis. The efferent ductules carry the seminal fluid from the rete testes to the epididymis.

Normal Scrotal Cartoon

Normal Scrotal Ultrasound e epididymis head, T tail of epididymus, Arrows- tunica albuginea

Normal Scrotal Ultrasound mediastinum

Mediastinum testis

The epididymis is composed of a head, body, and tail The epididymis is composed of a head, body, and tail. Its position is parallel to the testicle. The head of the epididymis (globus major) is located adjacent to the superior pole of the testis, and is the largest part of the epididymis. This is where the efferent ductules converge to form a single convoluted duct (ductus epididymis). The tail of the epididymis (globus minor) forms an acute angle and courses cephlad as the vas deferens (also known as the ductus deferens), which carries sperm from the epididymis in anticipation of ejaculation.

Epididymis cartoon

Epididymis Ultrasound

Sonographically, the epididymis is normally isoechogenic, or slightly hyperechoic than the testis. The appendix testis, a remnant of the Mullerian duct, is a small ovoid structure located beneath the head of the epididymis.   The appendix epididymis, representing a detached efferent duct, is a small stalk projecting off the epididymis. The dartos is a layer of muscle fibers, lying beneath the scrotal skin and dividing the scrotum into two chambers. The division of the two scrotal chambers is called the scrotal raphe.

The Tunica Vaginalis is a saccular extension of the peritoneum into the scrotal chambers. The inner or visceral layer of the tunica Vaginalis covers the testis and epididymis. The outer or parietal layer of the tunica Vaginalis, lines the scrotal chamber.  

Tunica vaginalis Cartoon

Testicular blood flow is supplied by the: Deferential artery Cremasteric (external spermatic) artery Testicular artery

The testicular artery divides into capsular and centripetal (intratesticular) branches. The centripetal arteries course along the septula converging on the mediastinum testis.  The spermatic Cord consist of Vas deferens Cremasteric, deferential, testicular arteries Pampiniform plexus of veins Lymphatics Nerves

Spermatic Cord cartoon

Spermatic cord ultrasound

Scrotum Part II Abnormal GERM CELLS: A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. A germ cell tumor is a neoplasm derived from germ cells.

Malignant Testicular tumors Most Extratesticular masses are benign, but the majority of intratesticular lesions are malignant. Most malignant testicular neoplasms are hypoechoic compared to the normal testicular parenchyma. All intratesticular masses should be considered potentially malignant until proven otherwise. Testicular neoplasms are the most common tumor in men 15 to 35 years of age. Germ cell tumors account for 95% of testicular tumors and include: Seminomas Teratomas Choriocarcinomas Mixed tumors

Seminoma Most common germ cell tumor in adults. Seminomas are radiosensitive and chemosensitive, resulting in the most favorable prognosis of all testicular tumors. There is an increased risk of developing a Seminoma in an undescended testis and the Contralateral normally located testis, even after orchiopexy (the surgery to move the undescended testicle into the scrotum). Seminoma spreads initially to draining lymph nodes in the retroperitoneum. When an intratesticular mass is discovered, the paraaortic region should be evaluated for lymph nodes.

Seminoma

Seminoma

Teratoma

Undescended testicle cartoon

Undescended testicle ultrasound

Prepubertal testicular tumors The most common prepubertal testicular tumor is the yolk sac tumor (endoermal sinus tumor). This is a germ cell tumor. Increased level of alpha-fetoprotein is seen with yolk sac tumors. The leydig cell tumor is the most common Gonadal stromal (non-germ cell) tumor in children and adults. They occur most frequently in boys aged 4-5 years of age. They are usually benign and produce testosterone leading to precocious puberty.

Yolk Sac tumor(endodermal sinus tumor)

Leydig Cell tumor

Consists of different germinal layers Teratomas Consists of different germinal layers endoderm: One of the three primary germ cell layers in the very early embryo mesoderm: Same as above ectoderm: Same as above

Teratoma

Teratomas are the second most common testicular tumor in children, and are usually benign. Teratomas in adults are usually malignant. They sonographically appear as well-defined masses containing cystic and solid components. Dense echogenic foci are common, representing calcifications, immature bone and fibrosis.  

Laboratory Values The following laboratory values are associated with certain testicular tumors: Beta-human chorionic Gonadotropin Choriocarcinoma Embryonal carcinoma Alpha-fetoprotein Yolk sac tumors

Choriocarcinoma Choriocarcinoma represents the most lethal and least common form of germ cell tumors. Unlike other testicular cancers that metastasize via the lymphatic system, Choriocarcinoma metastasized by hematogenous routes, thus patients present with distal metastases. Distal metastases (lug, liver, brain) may be the initial presentation. The primary testicular tumor may be small or non-palpable. Associated with an increase in Beta-Human chorionic Gonadotropin

Choriocarcinoma

Mixed Germ cell tumors These tumors contain different germ cell elements in various combinations. They are the second most common testicular malignancy after seminoma. The combination of teratoma and embryonal cell carcinoma is the most common mixed germ cell tumor. It has been called a teratocarcinoma in the past.

Mixed germ cell tumors

Testicular Metastases. Leukemia and lymphoma are the most common malignancies to affect the testis secondarily.

Testicular Metastases

Testicular Cysts There are two types of benign cysts: Cysts of the tunica albuginea Intratesticular cysts Intratesticular cysts are normally located near the mediastinum testis and probably originate from the rete testis.

Intratesticular Cyst

Tunica Albuginea

Cyst of the Tunica Albuginea

Epidermoid cysts The epidermoid cyst is a benign tumor of germ cell origin. These lesions are well – circumscribed solid tumors lying beneath the tunica albuginea. The cyst is filled with cheesy-white keratin, which is a fibrous protein. Sonographically, epidermoid cysts are well-defined, solid, hypoechoic masses with an echogenic capsule or onion ring pattern formed by multiple layers of keratin. Keratin is the essential element of hair and nails.  

Epidermoid Cyst

Testicular abscess Abscesses are usually a complication of epididymo-orchitis. Sonographically, abscesses present with an enlarged testicle containing a predominantly fluid-filled mass with hypoechoic or mixed echogenic areas.

Testicular Abscess

Scrotal Calcifications Calcifications (scrotal pearls) may be located within the testicle or between the layers of the tunica vaginalis.

Scrotal Calcifications

Testicular microlithiasis are frequently seen sonographically Testicular microlithiasis are frequently seen sonographically. Microlithiasis has not been proven to define a benign or malignant testicular condition.

Testicular Microlithiasis

Testicular infarct Testicular infarction commonly results from torsion or trauma. The Sonographic appearance depends on the age of the infarction. Initially, the infarction produces a focal or diffuse hypoechoic testicle. With time, the testicle decreases in size and develops areas of increased echogenicity representing fibrosis or calcifications.

Testicular infarct - Acute stage

Hydrocele A hydrocele is serious fluid that accumulates within the tunica vaginalis or between the layers of the tunica vaginalis (visceral and parietal layers) Hydroceles may be congenital or acquired. They may be idiopathic or the result of trauma, torsion, neoplasms, epidymitis or orchitis. Low-level echoes from fibrin or cholesterol crystals may be visualized within the hydrocele.  

Hydrocele adult

Hydrocele - fetus

A hematocele is seen when blood fills the scrotal chamber associated with trauma.

Hematocele

Varicocele A varicocele is a dilation of the pampiniform venous plexus (a bunch of veins located in the spermatic cord) of the testicular veins which drain the testicle. 90% of the varicoceles are on the left side. Varicoceles are the most common correctable causes of male infertility.   Incompetent spermatic venous valves lead to increased hydrostatic pressure in the venous system which dilates and leads to varicoceles. The left testicular vein drains into the left renal vein. The pressure in the left renal vein is higher than the IVC which explains the greater incidence of left varicoceles. Varicoceles should distend when a patient is standing, with Valsalva, or with abdominal compression. Due to the slow blood flow, varicoceles may become thrombosed.

Varicocele

varicocele

Scrotal Hernia This results from bowel protruding through the inguinal canal into the tunica vaginalis or the scrotum. The presence of peristalsis confirms the diagnosis. Small inguinal hernias can be visualized by using the Valsalva maneuver.

Scrotal Hernia

Scrotal hernia – one month old

Extratesticular tumors Extratesticular tumors usually involve the epididymis. The most common extratesticular tumor is the andenomatoid tumor.

Extratesticular Tumor-Hematocele

Spermatoceles Epididymal Cysts Spermatoceles are cystic masses of the epididymis that result from dilation of the epididymal tubules. Spermatoceles are more common than epididymal cysts. Epdidyjmal cysts are composed of clear fluid whereas spermatoceles are filled with thick milky fluid containing spermatoazoa. Both lesions result from prior episodes of epididymitis.   Sonographically both lesions MAY appear identical: anechoic, well-defined masses with no or few internal echoes. But usually, Spermatoceles, which usually occur at the epididymal head, will appear dense with echoes.

Spermatocele

Epididymal Cyst

The acute scrotum The two most common causes of acute scrotal pain are: Epididymitis/orchitis Torsion of the spermatic cord

Sonographically, epididymitis is associated with Acute epididymitis is the most common condition that causes acute scrotal pain Acute epididymitis is usually caused by sexually transmitted diseases in men under 35 years of age and urinary tract infections in men older than 35. Patients present with acute scrotal pain which may be associated with fever and pyruia. Sonographically, epididymitis is associated with Enlarged hypoechoic epididymis Hypoechoic testicle Increased blood flow (hyperemia) Reactive hydrocele Scrotal wall thickening The infection may extend into the testicle causing orchitis. Sonographically, orchitis is seen as an enlarged and hypoechoic testicle with increased blood flow.

Epididymitis

Testicular torsion   Typically, the testicle is attached to the tunica vaginalis. Without this attachment, the testicle can rotate freely on the spermatic cord (bell clapper deformity). This congenital anomaly, which can be found in as many as 12% of males, allows the testicle to twist, causing testicular torsion. Testicular torsion leads to venous occlusion and arterial ischemia causing infarction of the testicle. Torsion more often involves the left testicle. After 6 06 8 hours, the testicular salvage rate markedly decreases, and it is near 0% at 12 hours. Testicular torsion is observed in males younger than 3o years of age, with most aged 12-18. The patient typically presents with a sudden onset of severe unilateral scrotal pain.

Testicular torsion is a clinical diagnosis Testicular torsion is a clinical diagnosis. Imaging studies usually are not necessary and waste valuable time. Sonographically, with testicular ischemia, the testicle becomes enlarged, inhomogeneous and hypoechoic compared to the contra lateral testicle. The degree of torsion may vary between 180 – 540 degrees. Blood flow within the testicle would theoretically exclude the diagnosis of acute torsion, although the presence of flow does not exclude partial torsion.   Manual de-torsion is often performed in the emergency room. Testicles commonly rotate toward the mid-line. Manual detorsion involves rotating the painful testicle outward like opening a book.

Testicular torsion

Complete testicular torsion >12 hours

Testicular torsion Cartoon

Cryptorchidism   Cryptorchidism, literally means hidden testicle. and generally refers to an Undescended testicle. Testicles are usually descended at birth, although spontaneous descent may occur in the first year. Orchioplexy is the treatment of choice and is usually performed on patients aged 2-10 years. Infertility and cancer are complications of cryptorchidism. Patients with cryptorchidism have an increased risk of developing a malignancy in both the Undescended testis and the contralateral testis.

The most common location of the cryptorchid testis is in the inguinal canal or prescrotal positions. Less than 10% of Undescended testis are located in the abdomen. Anorchia or congenital absence is rare and accounts for only 4% of patients who present with cryptorchidism.  

Ct and MRI are typically used to image an abdominal testis Ct and MRI are typically used to image an abdominal testis. although imaging posterior to a filled bladder may aid in the abdominal evaluation by ultrasound NOTE: looks like an enlarged lymph node when seen.

Cryptochidism

Cryptochidism