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Scrotum

STUDY
PLAY
Anatomy covered in male pelvis
*Scrotum & contents
*Penis
*Prostate
Where do the testicles develop?
Fetal abdomen near kidneys
Testicular Development (up until 7th month)
~ 4th month, testicles descend to level of bladder
Remain here until 7th month
Testicular Development (after 7th month)
Testicles descend thru inguinal canal to scrotum (after 7th month, usually during last month of gestation)
What causes the testicles to descend?
Hormones
Process vaginalis
Evagination of peritoneum traels thru inguinal canal from abdomen into scrotum
Testicular Development (5th week)
*Testis begin primary descent
*Kidneys begin ascent
Testicular Development (8th - 9th week)
Kidney reaches adult position
Testicular Development (7th month)
*Testis at internal inguinal ring
*Gubernaculum (in inguinal fold) thickens & shortens
Testicular Development (Postnatal life)
*Testis in scrotum
*Processus vaginalis closed
*Gubernaculum (vestigial)
Scrotum
*Pouch of skin continuous w/ abdomen
*Suspended from base of male pelvis btw perineum & penis
What is the scrotum derived from?
Labioscrotal folds -- swells under influence of testosterone to form scrotal sacs
Median raphe
point of fusion of twin sacs
Purpose of Scrotum
*Protective casing
*Maintain testicular temperature (2° C below intrabdominal temp)
Contents of Scrotum
*Testicles
*Epididymis
*Proximal part of vas deferens
Testicles (Testes)
Male gonads
Oval shaped, symmetric
US Appearance of Testes
Appear as smooth medium gray structures w/ fine echo texture
What is each testis made of
Divided into ~ 250-400 lobules that contain seminiferous tubules
Tubuli recti
formed by seminiferous tubules
20-30 larger ducts
Size of Testes
Length: 3 - 5 cm
A-P: 3 cm
Width: 2 - 4 cm
(size & wt decrease w/ age)
Function of testes
*Produce sperm & testosterone
*95% of testosterone is secreted by Leydig cells in testicles
*Endocrine (testosterone) & Exocrine functions
TUnica albuginea
*Echogenic, dense fibrous capsule surrounding testes (covered by tunica vaginalis)
*Multiple septa are formed from tunica albuginea & converge at mediastinum testis
*Form lobules in tests
Mediastinum testis
*Posterior portion of tunica albuginea reflects into testis forming vertical septum
*Supports testicular vessels & ducts
US appearance of Mediastinum Testis
*Sometimes seen as echogenic band going thru testicle
*Echogenic line that runs from superior to inferior pole of testicle
*Parallel to epididymis longitudinally
Tunica vaginalis
Serous membrane (formed by peritoneum) that partially covers testicle
*Small amount of fluid btw 2 layers nml
*Layers not normally seen on US
2 layers of tunica vaginalis
Inner (visceral) layer
Outer (parietal) layer
Visceral layer of tunica vaginalis
Covers:
*Testis
*Epididymis
*Lower spermatic cord
Parietal layer of tunica vaginalis
Lines wall of scrotal pouch
Seminiferous Tubules
*Contained w/in tests
*Converge at apex of each lobule & anastamose
Tubuli recti
Enter mediastinum to form rete testis in medastinum testis
Rete testis
drains into head of epididymis thru efferent ductule
Epididymis
*Single, tightly wrapped tube
*6-7cm
*Begins superiorly & courses posterolateral to testis
Parts of epididymis
Composed of:
*Head
*Body
*Tail
*Appendix
Function of epididymis
Aids in sperm maturing as well as concentrates, stores, & transports sperm
Epididymal Head
AKA Globus Major
*Measures 10-12mm diameter
*Adjacent to superolateral pole of testis
*Largest portion of epididymis
*Formed by 10-15 efferent ductules from rete testis joining together
Epididymal Body
*Smaller than head
*Posterolateral margin of testicle
Epididymal Tail
AKA Globus Minor
*Slightly larger than body
*Inferior to testis
Appendix Testis
*Small protuberance on head
*Commonly seen when hydrocele present (excess fluid in scrotum)
*Susceptible to torsion
Seminal Vesicles
*Convoluted pouchlike structures that empty into distal ductus deferens to form ejaculatory ducts
*Paired glands, encapsulated by connective tissue
US Appearance of Seminal Vesicles
Appear as low level echoes SUPERIOR to prostate
Vas Deferences
*Continuation of ductus epididymis
*Thicker & less convoluted
*Dilates at terminal end near seminal vesicles
What forms the spermatic cord
*Vas deferens
*Testicular arteries
*Venous pampiniform plexus
*Lymph system
*Nerves
*Fiber of cremaster
Spermatic cord
*Connects abdomen & scrotum (suspends testis in scrotum)
*Bound by fibrous shealth
*Lies directly under skin
Arterial supply of spermatic cord
*Testicular artery (from aorta)
*Deferential artery
Venous drainage of spermatic cord
Pampiniform venous plexus
Verumontanum
Junction of ejaculatory ducts & urethra
Capsular arteries
*Tunica vasculosa
*Branch over surface of testis
Centripetal arteries
*Arise from capsular arteries
*Course from surface to mediastinum along septa
*Curve backwards forming recurrent rami (centrifugal arteries)
*Arterioles to capillaries
Cremasteric artery
Provides flow to cremaster muscle & peritesticular tissue
Deferential artery
Supplies epididymis & vas deferens
Cremasteric & Deferential arteries
*Accompany tescticular artery w/ spermatic cord
*Supplying extratesticular structures
*Anastomose w/ testicular artery to provide some flow to testis
Venous Drainage: Pampiniform plexus
*Exits from mediastinum testis into spermatic cord
*Converges into 3 veins (testicular, creamsteric, deferential)
Right testicular vein
Drains directly into IVC
Left testicular vein
Drains into LRV
US Appearance of Testis
*Homogeneous texture (echogenicity increases w/ age)
*Oval glands measure:
- Long 3 - 5 cm
- Wide 2 - 4 cm
-AP 3 cm
*Wt: 12.5 - 19 g
*Volume: 15 - 20 cc
Volume formula
(Length x Width x AP) x .523
Clinical History
*Palpable lesions should be palpated
*Does pt have pain? Which side? When doing what activity?
*Lumps, swelling, etc should be noted
*Any recent illness? UTI, etc.
Testicular Ultrasound
*Utilize high frequency linear transducer (>7.5 MHz)
*One image to compare both testes (size & echogenicity)
*Both testicles scanned completely
*Spermatic cord area should be scanned from inguinal canal to scrotum
*? Free fluid
*Layers not normally seen
*Important to scan nml protocol plus dedicated images labeled "area of interest" if indicated
Images Required for Testicular Ultrasound
-Longitudinal -- lateral, middle, & medial portions
-Transverse -- upper, middle, & lower planes
Epididymal Ultrasound
*Head, body, & tail should be images
-Head superior to upper pole of testicle
*Slightly hyperechoic
*More coarse than testicle
Hydrocele
*Space between layers of tunica vaginalis contains excess serous fluid
*Most common cause of painless swelling
*Epididymis attaches to testicular wall posteriorly, fluid only in anterolateral portion
Simple Hydrocele
Completely anechoic
Reactive Hydroceles
*Contain echoes in fluid
*Caused by trauma, infection, torsion, or tumor
Hematocele
*Less common than hydroceles
*May contain septations
*Wall of scrotum becomes thickened
Causes of hematocele
*Surgery
*Trauma
*Diabetes
*Torsion
*Neoplams
Pyoceles
Abscesses that rupture
Cryptorchidism
*Normal variant
*Testicles fail to descend into scrotum
*Normal testicle is larger & more echogenic than undescended one
Reasons for cryptochidism
*Short spematic cord
*Narrow inguinal canal
*Fibrosis
*Adhesions
Locations of undescended testicles
*Abdomen
*Inguinal canal (most common, 62%)
*External Inguinal ring
2 possible complications of cryptochidism
*Infertility
*Cancer
Treatment of cryptochidism
*Orchipexy for infants & children
*Orchiectomy for pubertal & young adults
US of Testicles in children
*Very high frequency transducer due to superificial nature of inguinal canal
Polyorchidism
*Supernumary testis - many testis
*Can be found anywhere along descent path
*Attached to normal testis by duplicated vas deferens
*Functions normally if within scrotum
Varicocele
*Dilated veins from obstruction of venous return
*Always larger on left than right
*Most palpable & not always painful
2 types of varicocele
*Idiopathic
*Secondary
Idiopathic Varicoceles
*Most common correctible cause of infertility
*98% occurs on left side in ages 15-25
*70% have bilateral varicoceles
Ways to show Varicoceles on US
*Increase venous preassure to show dilated veins
*Valsalva manuever in upright position (veins relax when pt is supine)
*Color flow doppler can show change in direction of flow when pt strains, indicating no valves in veins
Secondary Varicoceles
*From extreme pressure on spermatic vein, enlarged liver, abdominal masses or retroperitoneal mass compressing veins (left renal cell ca)
*Pt position does not affect secondary varicoceles
US apperance of Varicoceles
*Numerous anechoic structures
*Measure more than 2 mm in diameter
*Occurs in pampniform plexus medially
*Varicoceles follow spermatic cord to inguinal canal
*Can be compressed easily by transducer
Microlithiasis
*Scattered, tiny, punctate foci thru/o testicle
*May be unilateral or bilateral
*Found to have significant associated w/ testicular cancer
Hernia
*Scrotal hernias are from inguinal hernias that slip into scrotum
*Excessive straining or lifting heavy things are common causes
2 types of hernias
*Direct (caused by weakening of flood of inguinal canal)
*Indirect - most common (occur when intestines escape from abdominal cavity thru inguinal canal into scrotum)
Symptoms of hernia
*Scrotal swelling
*Palpable, firm area w/in scrotum
*Lower abdominal pain
US Appearance of Hernias
*Scrotal mass w/ both echogenic & anechoic areas
*Peristaltic motion can be detected w/in mass
Caution with US of Hernias
*WARNING:
-Hydroceles & hematoceles w/ fibrous septations may appear like fluid filled bowel loops
-Inflammed spermatic cord also mimics hernia
*SO:
-Document peristalsis & use color flow
Epididymitis
*Inflammation of epididymis
*Most common cause of acute scrotal pain in adults
*Mostly unilateral
*May be focal or whole epididymis involved
Causes of epididymitis
*Lower UTI infection (most common) spread thru spermatic cord
*Mumps
*Syphillis
*Virsues
*STDs (very common)
US Appearance of Epididymitis
*Thick, enlarged epididymis, decreased echoes in affected area
*Thickening of scrotal skin
*Reactive hydrocele
*Doppler shows increased blood flow in affected area
*May be isolated to head or tail
Epididymo- Orchitis
*Infection of both epididymis & testicle
*Epididymitis spreads to testicle 20-40% of cases
*Compare Left & Right sides (2d & color doppler)
*Testis enalrged
*May be focal abnormality or be entirely affected
*Hydrocele, hematocele, or pyocele may be present
*Scrotal wall thickening
*May lead to infarct or abscess formation
Fournier's Gangrene
*Uncommon type of gangrene affecting soft-tissue of genital organs
*Type of necrotizing fasciitis
Causes of Fournier's Gangrene
*Infection (UTI)
*Urethral injury/stricture
*Trauma (piercings)
*HIV
Treatment of Fournier's Gangrene
*Debridement of entire scrotum, & occasionally penis
*Usually requiring major reconstructive surgery w/ skin grafts
Epididymal Cysts
*Symptomatic
*Can develop thru/o epididymis
Spermatocele
*Retention cysts of small tubes that hold sperm
*May cause anterior or inferior displacement of testicle
*Single or multiple
*Asymptomatic, no clinical significance until symptomatic, then surgically corrected
*Most common type of epididymal cyst
*Cystic mass that cause anterior displacement of testicle
*May have septations
*May include fat, cell debris, sperm
*Can appear identical to epididymal cysts
-True epididymal cysts contain only serous fluid
-Needle aspiration can differentiate
*Range from .2 to 9cm in size
Tunica Albuginea Cysts
*Size range from 2-5mm
*Present as palpable lumps
*Usually asymptomatic
*50-60 years old males
*Cause unknown
Torsion
*Results from weakening of attachment of mesenteric from spermatic cord to testicle
*Must be treated w/in 5-6 hours of onset
*Occurs when remnant stalk of tunica vaginalis is twisted causing restriction/obstruction of blood flow to testicle
*Surgical emergency in acute phase
*Testis must be untwisted to restore blood flow
Symptoms of Torsion
*Sudden onset of extreme scrotal pain begins while resting
*Some experience nausea/vomitting
Who is torsion most common in?
Children & teenage boys but can occur at any age
Bell-clapper deformity
Tunica vaginalis completely surrounds testis, epididymis & spermatic cord, can rotate freely in scrotum
Attachment of scrotum & testicle
Testicle attached to scrotum by remnant stalk of tunica vaginalis at barea area
Classifications of torsion
*Classified by time elapse since onset
*Acute
*Subacute
*Chronic
Acute torsion
*Doppler flow shows decreased arterial flow to testis
*No venous flow (unless torsion-detorsion situation)
*1-6 hours, epididymis & testis enlarge, hypoechoic, scrotal skin edema & hydrocele may appear
Subacute torsion
*24 hours to 10 days
*Anechoic areas seen in testis, epididymis has mixed echogenicity w/ increased & decreased echoes
Chronic torsion
*after 10 days onset
*Doppler shows no flow, testis is not salvageable
*Testis atrophies but epididymis stays larger & hyperechoic
US of torsion
*MUST doppler both intratesticular artery & vein
*Doppler of peripherally located vessels not acceptable --must be intratesticular
*Difficult to r/o torsion/detorsion
*In acute phase, occluded veins cause swelling of affected testicle
*As torsion continues, arteries affected
*Arterial occlusion followed by ischemia
*Salvage rate determined by time of diagnosis
*Missed torsion diagnosis common cause of lawsuits
Salvage rate
*W/in 5-6 hours -- 80-100% salvageable
*Btw 6-12 hours - 70% salvageable
After 12 hours - 20% salvageable
Incomplete torsion
Venous flow may be obstructed by there is enough arterial presure to allow arterial flow into testicle
Testicular Rupture
*Must be diagnoses early
*Blunt trauma is most common cause
*90% can be saved if surgery is performed w/in 72 hours
*Treamtent - repair or removal
*Several scrotal pain & swelling
US Appearance of Testicular Rupture
*Focal areas of altered echogenicity
--hemorrhage
--infection
*Contour of testicle is irregular
*Color flow can be used to avoid mistaking complex hematoma for rupture
Scrotal Pearls
*Calcifications seen floating rreely w/in scrotal sac or on tunica
*Unknown cause
*Usually no clinical significance
Infarction
*May be due to torsion, trauma, infection
*Have varying echo pattern
*Neoplams may be difficult to distinguish from infarcts however infarcts decrease over time & neoplams enlarge
Infraction echo patterns
*Initially hypoechic mass in testis, testis normal size & echo texture
*Later area of infarct decreases in size w/ areas of increased echogenicity due to fibrosis or calcification
Malignant Tumors
*Detection rate of intratesticular masses by US in near 100%
*US can distinguish btw intratesticular & extratesticular masses w/ high accuracy (98-100%)
*All intratesticular masses malignant until proven otherwise
Malignant Tumors Appearance
*Hypoechoic
*Painless, unilateral scrotum enlargement
*Palpable scrotal mass
*Hardness of testicle
*May mimic benign processes as well
*Highly vascular w/ normal testicular parenchyma (in focal cancers)
*Scrotal wall usually not thickened
*Focal malignancies have distinct borders
Germ cell tumors
*Some have elevated hCG and/or AFP
*Generally highly malignant
Malignant Tumor Facts
*1-2% of cancers in men
*But most common malignancy in 15-35 year olds
*Of germ cell tumors, 60% of one type only, & rest are more than one type
*Risk factor: undescended testes - 2.5-8X higher
*95% are of germ cell origin
Germ cell tumors: 2 types
*Seminomas
*Non-seminomatous GCT
Subtypes & frequencies of GCT
*Seminomas (40%)
*Embryonal (25%)--NSGCT
*Teratocarcinoma (25%)--NSGCT
*Teratoma (5%)--NSGCT
*Choriocarcinoma (pure) (1%)--NSGCT
Non-seminomatous germ cell tumors (NSGCT)
*Affect younger men (20s-30s)
*More aggressive than seminomas
*Frequently have visceral metastases
Seminoma
*Most common malignant tumor of testicle
*most common component of mixed GCTs
*40-50% primary testicular tumors
*Peak incidence 4th & 5th decades
*Least aggressive of testicular tumors, best prognosis of all testicular tumors (close to 100%)
*Most common cancer in cryptorchid testes
US appearance of Seminoma
*Solid homogeneous, hypechoic mass
*Varies in size & shape
*Scattered hyperechoic areas may be w/in mass
*Margins are grossly not irregular but contour varies
*External anatomy enlarged & distorted
Mixed germ cell tumors
8Most common NSGCT tumor
*Contain various combinations of germ cell elements
*Teratocarcinanoma (teratoma + chorichocarcinoma) most common combination
*Mixed GCTs are second most common 1° testicular malignancy, second only to seminomas
*40% of all germ cell tumors
Embryonal cell Carcinoma
*Pure embryonal cell cancer is rare
*Usually small but can replace some or all of testicle w/o enlargement
*When small, hypoechoic
*With enlargement, become heterogeneous
*More aggressive than seminomas, invading tunica albuginea
US Appearance of Embryonal cell carcinoma
*Hypechoic mass in testicle
*Homogeneous
*Margins poorly defined
*Focal hyperechoic areas may be seen due to hemorrhage or necrosis
*Children w/ this tumor demonstrate rapid testicular enlargement
Teratoma
*5-10% of 1° of testicular tumors
*Tissue matter can be found w/in mass (bone, soft tissue, skin, teeth, fat, hair, fluid)
*Once thought to be benign, untreated, 1/3 metastasize in 5 yrs
*5-year survival 70%
*Tend to be malignant in adults
US Appearance of Teratoma
*Well-defined
*Markedly heterogeneous appearance w/ regions of shadowing
*Cystic & solid parts
*Shadowing due to bone, teeth, matted hair
Choriocarcinoma
*Least common
*Pure chorcio ca. very rare (< 0.5%)
*1-3% primary
*Affects men 20-30 years old
*Elevated hCG levels which leads to gynecomastia
*Highly aggressive malignant tumors
*Mass too small to palpate, but pts complain of scrotal pain
US Appearance of Choriocarcinoma
*Small mass w/ mixed echoes - heterogeneous echo texture
*Prognosis is poor
*Rapid mets
*Radiation & chemo not effective
Occult Primary Tumors
*Some pts present w/ METs &/or DVT
*Scanning of testicles reveals one or more coarse foci of calcifications
*Called burnt out tumors as they are cancers that have regressed
*Tumor grows & spreads so fast that it burns out its own blood supply
Metastatic disease
*METs to testicle rare
*If happens, usually men 60-70 years old
*Most common is prostate & kidney
*Less common: bladder, bowel, lung
*Appearance varies dependent upon primary lesion
Lymphoma
*Make p 1-7% of all testicular tumors
*Most common bilateral 2ndary neoplasm of testicle > 60 years of age
*Leukemia also may involve testicle (usually in children)
*Homogeneous, hypoechoic masses, often multiple
Staging of tumor: Stage 1
Confined to testis w/ or w/o adnexal invasion
Staging of tumor: Stage 2
Mets to retroperitoneal lymph nodes but not beyond
Staging of tumor: Stage 3
Mets beyond retroperitoneal lymph nodes to other sites
Scrotal Sonography: Scanning Techniques
*Testes scanned in 2 planes: long & transverse
*Views to include: superior, middle, & inferior portions as well as medial & lateral
*Adjacent epididymis should be seen
*Size, echogenicity of each testicle & epididymis should be compared to other side
*2D & color should be compared, w/ both tests on same image if possible
*Scrotal skin thickness should be noted
*Blood flow should be documents in testes & surrounding scrotal contents
*Use of color & doppler for differentiating torsion & epididymitis in "acute scrotum" setting
*Comparison of both sides should be done
* Contents of scrotal sac should be examined for extratesticular mass, fluid collection, other abnormalities
Scrotal Sonography: Room Settings
*Valsalva manuever or upright position for better visualization
*Room should be kept comfortable
*Use warm gel (prevents cremaster muscle from contracting, drawing up testicle)
*Scrotum should be draped & supported using towels (protect modesty as much as possible)
*Pt in comfortable supine position, semi-frog legged
*Thorough history taken including palpation of scrotal area if palpable mass is present
What is least common testicular cancer?
Choriocarcinoma
Most common malignant tumor of testicle?
Seminoma
Most common type of epididymal cyst?
Spermatocele
What is most common correctable cause of infertility?
Idiopathic Varicoceles
Most common location of cryptorchidism?
Inguinal canal (62%)