Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with Tc-99m constitutes a co-ordination complex in which ligands bond to a central atom of Tc-99m by co-ordinate covalent bonds 4 .
The radioactive te...
Teratomas are germ cell tumors that arise from ectopic pluripotent stem cells that fail to migrate from yolk sac endoderm to the urogenital ridge during embryogenesis. By definition, they contain elements from all three embryological layers: endoderm, mesoderm and ectoderm although frequently, e...
Testicular abscess is usually a complication of severe epididymo-orchitis and needs to be distinguished from other testicular pathology that may present with similar clinical or imaging features.
The majority of patients develop a testicular abscess as a result of untreated or se...
Testicular adrenal rests are a rare cause of a testicular mass.
Testicular adrenal rests can be known by a variety of terms 2:
testicular adrenal rest tumor (TART)
testicular adrenal rest tissue
testicular tumor of the adrenogenital syndrome
testicular adrenal-like tissue
Testicular and scrotal ultrasound is the primary modality for imaging most of the male reproductive system. It is relatively quick, relatively inexpensive, can be correlated quickly with the patient's signs and symptoms, and, most importantly, does not employ ionizing radiation.
MRI is occasion...
Testicular and epididymal appendages are remnants of embryonic ducts and are quite common, with one or more being present in ~70% of patients 1.
Four such appendages have been described:
testicular appendix (hydatid of Morgagni)
it is a Müllerian duct remnant (paramesonephric d...
A testicular appendix (alternatively called appendix of testis or appendix testis, and historically also known as hydatid of Morgagni) represents a developmental remnant of the paramesonephric duct (Müllerian duct) which is situated in the upper pole of the testis inside a groove between the tes...
The testicular arteries (also known as the spermatic arteries) are the long, small-diameter gonadal arteries in the male that supply the testis alongside the cremasteric artery and the artery to the ductus deferens.
As paired structures they arise symmetrically, slightly...
Testicular cancers are the most common neoplasm in men between the ages of 20 and 34 years.
Testicular cancer is uncommon, accounting for less than 1% of all internal organ malignancies 2.
The demographics of affected individuals depends on the age of the histology of the tumor. ...
The staging for testicular tumors is performed according to the TNM system with staging groupings. It can be remembered in its abbreviated form as:
stage I: confined to testis, epididymis, spermatic cord, scrotum
stage II: lymph nodes involved but no distant metastases and serum tumor markers...
Testicular choriocarcinoma is a type of non-seminomatous germ cell tumor.
Incidence peaks at around 20-30 years of age.
Can be variable with some patients initially presenting with metastates.
It is most commonly detected as a component of a mi...
Simple testicular cysts are usually nonpalpable and thus are detected incidentally.
Testicular cysts require no treatment when discovered.
anechoic with posterior acoustic enhancement
no flow on color Doppler
Testicular descent occurs after the fourth month of fetal life. The testes are derived from the gonadal ridge medial to the mesonephric ridge of the intermediate cell mass. An elongated diverticulum of the peritoneal cavity, the processus vaginalis precedes the testis through the inguinal canal ...
Testicular dislocation is a rare condition in which a testicle is dislocated from its normal position within the scrotum to another location, most commonly the superficial inguinal pouch.
The condition mainly occurs in younger men with a mean age of 25 years 2.
Testicular embryonal cell carcinoma is a type of non-seminomatous germ cell tumor.
Incidence peaks at around 25-30 years.
It may occur as part of a mixed germ cell tumor (more common and may be present as a component in around 80% of mixed germ cell tumors) or very ra...
Testicular epidermoid cysts, also known as keratocysts, are rare benign tumors.
Testicular epidermoid cysts account for around 1-2% of all testicular masses and typically present in mid-adulthood (2nd to 4th decades) 1,2. They are the most common type of benign testicular neoplasm...
Testicular fracture refers to a break in the parenchyma of the testicle as a result of blunt trauma.
A fracture line can be seen as a hypoechoic and avascular area within the testis but is only seen in 17% of cases 1. A tunica albuginea rupture may also be pr...
Testicular germ cell tumors account for 90% of primary tumors of the testes. They are the most common nonhaematologic malignancy in men 15-49 years old.
They are divided into:
testicular seminoma: 40% of germ cell tumors 1
non-seminomatous germ cell tumor: 60% of germ cell tumors
Testicular lipomatosis is a rare condition characterized by homogeneously hyperechoic non-shadowing lesions within the testes on ultrasound without flow on color Doppler. It is seen as a component of PTEN (phosphatase and tensin homolog (gene)) hamartoma tumor syndrome which includes:
Testicular lymphoma is an uncommon testicular malignancy. Lymphoma can involve the testes in three ways:
primary site of extranodal disease (primary testicular lymphoma)
secondary involvement of systemic disease
primary manifestation of subclinical systemic disease
This article is concerned ...
Testicular microlithiasis is a relatively uncommon condition that represents the deposition of multiple tiny calcifications throughout both testes.
The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In the ...
Testicular mixed germ cell tumors are, as the name suggests, testicular tumors composed of two or more types of germ cell tumor. They are considered to be part of non-seminomatous germ cell tumors, as it is that component which dictates prognosis and treatment.
Overall they account for over 10...
Testicular sarcoidosis is a rare manifestation of sarcoidosis. In cases of urogenital sarcoidosis, more commonly the epididymis is affected.
Testicular sarcoidosis is more common in African-American patients, as are other forms of sarcoidosis 1. Up to 5% of patients with chronic s...
Testicular seminomas are a type of germ cell tumor and the most common testicular tumors, accounting for ~45% of all primary testicular tumors. This article concerns itself only with testicular seminomas; however, seminomas can arise outside of the testicle; most often within the anterior medias...
Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behavior, and often exists as part of testicular mixed germ cell tumors.
Pure testicular teratomas account for only 4-9% of all testicular tumors. A similar number are seen in the context of test...
Testicular torsion occurs when a testicle torts on the spermatic cord resulting in the cutting off of blood supply. The most common symptom is acute testicular pain and the most common underlying cause, a bell-clapper deformity. The diagnosis is often made clinically but if it is in doubt, an ul...
Testicular trauma is the third most-common cause of acute scrotal pain and may result in various degrees of damage to the testes.
Testicular rupture and testicular ischemia/infarct are two severe complications which need to be ruled out. Other injuries that can occur include 1:
Testicular vasculitis can occur as either part of a systemic vasculitis or an isolated vasculitis involving only the testes with both having roughly equal prevalence.
The mean age of onset is approximately 40 years.
Symptoms can include a testicular mass w...
Testicular yolk sac tumors (also known as endodermal sinus tumor of the testis) is the most common childhood testicular tumor (80%), with most cases occurring before the age of two years 1. In adults, pure yolk sac tumor is extremely rare, however mixed germ cell tumor is commonly seen.
The testes (singular: testis), also known as the testicles, are the male gonads and are contained within the scrotum. The testes are responsible for the production of sperm and testosterone.
At birth, testes measure approximately 1.5 cm (length) x 1 cm (width), reaching ~4 mL vol...
Thimble bladder is a descriptive term for extreme fibrosis and contracture of the bladder walls, resulting in a tiny bladder. The term is usually used to describe changes from advanced genitourinary tuberculosis.
The threads and streaks sign refers to an angiographic appearance of a vascularized tumor thrombus extending into the ipsilateral renal vein or the inferior vena cava from a renal cell carcinoma. This gives an appearance of linear, thread-like or string-like appearance of the involved vessel.
Throckmorton sign, also known as John Thomas sign, refers to when the penis points in the direction of unilateral disease, typically of the pelvis or hip.
Throckmorton sign is a slang term used humorously by medical students and residents.
According to the first serious study of the sign publ...
Thrombosis of the pampiniform plexus is a rarely reported phenomenon of the formation of thrombus within the pampiniform plexus of the testes. It may occur with or without a varicocele. Its exact etiology is not well known but has sometimes been seen following epididymo-orchitis 1. Spontaneous o...
Torsion of the appendix testis (occasionally called torsion of the hydatid of Morgagni) is the most common cause of an acute painful hemiscrotum in a child. The appendix testis is located at the upper pole of the testis (between the testis and the head of the epididymis).
The normal appendix te...
Total pelvic exenteration refers to extensive surgical resection of pelvic structures to treat locally advanced or recurrent pelvic malignancies. It is performed to obtain optimal excision of tumor radical margins which can be difficult in pelvis given proximity and often local invasion of adjac...
Transitional cell carcinomas of the urothelium are graded histologically as follows:
transitional cell papilloma
benign tumor, not a carcinoma but sometimes included in classification systems
carcinoma in situ
do not penetrate the basement membrane
cells resemble those of grade II or III t...
Transitional cell carcinoma of the bladder staging uses the TNM system which has replaced the previously widely used Jewett-Scott-Marshall tumor staging system. It is very similar to the staging of TCC of the renal pelvis and staging of TCC of the ureter.
Ta: non-invasive papill...
Transitional cell carcinoma of the renal pelvis staging uses the TNM system and is very similar to staging of TCC of the bladder and to staging of TCC of the ureter.
Ta: noninvasive papillary tumor
Tis: in situ (noninvasive flat)
T1: through lamina propria into sub-epithelial ...
Transitional cell carcinoma of the ureter staging uses the TNM system and is very similar to staging of TCC of the bladder and to staging of TCC of the renal pelvis.
Ta: noninvasive papillary tumor
Tis: in situ (noninvasive flat)
T1: through lamina propria into sub-epithelial...
Transitional cell carcinoma (TCC) of the renal pelvis, also called urothelial cell carcinoma (UCC) of the renal pelvis, is uncommon compared to renal cell carcinoma and can be challenging to identify on routine imaging when small.
This article concerns itself with transitional cell carcinomas ...
Staging of transitional cell carcinomas of the urinary tract vary according to the location of the tumor, and are staged using the TNM staging system.
transitional cell carcinoma of the renal pelvis
transitional cell carcinoma of the ureter
transitional cell carcinoma of the bladder
Transitional cell carcinoma (TCC) of the ureter, also called urothelial cell carcinoma (UCC) of the ureter, are uncommon compared to similar tumors elsewhere along the urinary tract but are nonetheless the most common primary tumor of the ureter.
This article concerns itself with transitional c...
Transitional cell carcinoma (TCC), also called urothelial cell carcinoma (UCC) of the bladder, is the most common primary neoplasm of the urinary bladder, and bladder TCC is the most common tumor of the entire urinary system.
This article concerns itself with transitional cell carcinomas of the...
Transitional cell carcinoma (TCC), also called urothelial cell carcinoma (UCC), is the most common primary malignancy of the urinary tract and may be found along its entire length, from the renal pelvis to the bladder.
As imaging findings and treatment vary according to where along the urinary...
Transition zone may refer to the:
transition zone of a nerve
zone of transition of a bone lesion
transition zone (TZ) of the prostate
Transjugular renal biopsy can be performed to obtain an adequate tissue sample for histopathologic diagnosis on renal dysfunctions. It is usually performed in high-risk patients in whom percutaneous renal biopsy is not feasible or is contraindicated. This is also useful in morbidly obese patient...
Transplant renal arterial pseudostenosis is uncommon. It is a lesion in the iliac artery proximal to the implantation of the transplant renal artery.
Uncommon, although as the population of renal transplant recipients has become older and more diabetic, the incidence of this disea...
Transrectal ultrasound (TRUS) is a technique that is used most commonly to evaluate
the prostate gland, including ultrasound-guided prostate biopsies
depth of invasion of colon/rectal cancer (for staging purposes)
It can also be used for guidance in placing a transrectal drain, or in rare pro...
Transrectal ultrasound–guided prostate biopsy is considered the standard approach for prostate biopsy and is most commonly performed on an outpatient basis following positive screening for prostate cancer. It is not a targeted biopsy procedure.
Nowadays it is possible to perform targeted samp...
Transureteroureterostomy (TUU) is a procedure in which one ureter is divided and then connected (re-routed) into the other. It is performed when a distal ureter needs to be bypassed and can be performed instead of a psoas hitch or Boari flap. It may be preferable if the patient has had prior rad...
Transurethral resection of the prostate (TURP) is a traditional therapy for lower urinary tract symptoms (LUTS) and prostatism from benign prostatic hyperplasia. TURP results in characteristic imaging features.
acute urinary retention
The transverse perineal muscles are important for the stability of the pelvic and perineal structures via their intimate relationship with the perineal body. For many years, it was thought that these muscles directly inserted into the perineal body. It is now known that fibers from the muscles o...
True hermaphroditism is a form of disorder of gender development.
Patients with true hermaphroditism have mosaicism of 46XX and 46XY. They therefore have both ovarian and testicular tissues.
There are three forms of true hermaphroditism:
unilateral true hermaphroditism
Tuberous sclerosis, also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterized by the development of multiple benign tumors of the embryonic ectoderm (e.g. skin, eyes, and nervous system).
Tuberous sclerosis has an in...
The tuberous sclerosis diagnostic criteria have been developed to aid the diagnosis of tuberous sclerosis and have been updated in 2012 by the International Tuberous Sclerosis Complex Consensus Group (at time of writing - 2019) 1.
The identification of either a TSC1...
Tubular ectasia of rete testis (rare plural: retia testes 8) represents dilated testicular mediastinal tubules.
This condition is more common in men over the age of 55 years.
It is often bilateral, is frequently associated with spermatoceles and may occur as result of a vasectom...
Tubular ectasia of the epididymis results in enlargement of the epididymis with multiple cystic interfaces. It typically occurs in those with a prior vasectomy but can be also seen with other causes of obstruction of the ductus deferens.
Tubulocystic renal cell carcinomas are a rare subtype of renal cell carcinoma (RCC) with predominantly cystic appearance.
Tubulocystic RCC was first identified as a distinct histopathologic entity in 2005, and subsequently acknowledged as an independent disease category in the 2016...
The tulip sign is a sonographic clue for in-utero diagnosis of severe hypospadias.
The configuration of a tulip is given by the severe curvature of the penis in association with the penoscrotal transposition of a bifid scrotum.
Tumors of the male urethra are uncommon. They can be categorized both on the grounds of histology and location.
squamous cell carcinoma of the urethra: 80%
urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra)
adenocarcinoma of the urethra: 5%...
Tumors of the seminal vesicles usually represent contiguous invasion of the seminal vesicles from malignancies in adjacent organs, most commonly the prostate. Tumors originating de novo within the seminal vesicles themselves are much rarer.
adenocarcinoma of the seminal vesic...
Tunica albuginea (TA) cysts are the most common extratesticular benign scrotal mass lesion. They are a type of scrotal tunica cyst.
Their mean age at presentation is 40 years (although may be seen in the 5th and 6th decades).
They are usually palpable.
The tunica albuginea (TA) forms the fibrous covering of the testis and is itself covered by the serous layer, the tunica vaginalis. The covering is total, except for at the point of attachment of the epididymis, and a small defect posteriorly where the spermatic cord vessels enter and leave the ...
Tunica is a word used in anatomy to refer to a type of covering.
tunica adventitia (also known as tunica externa)
tunica albuginea (clitoris)
tunica albuginea (ovary)
tunica albuginea (penis)
tunica albuginea (testis)
Tunica vaginalis cyst is a type of benign paratesticular cystic lesion. It is a cyst that arises from the tunica vaginalis and, in conjunction with tunica albuginea cysts, they are collectively termed scrotal tunica cysts.
Their exact cause is unknown, although history of trauma, hem...
The tunica vaginalis (TV) represents the investing serosal covering of the testis. It forms as the embryological testis descends and passes out through the superficial inguinal ring carrying its abdominal peritoneal covering with it.
The tunica vaginalis is said to consist of two layers, the pa...
Tunica vaginalis testis mesothelioma refers to mesothelioma arising from the tunica vaginalis.
Malignant mesothelioma originating from the tunica vaginalis is extremely rare.
Patients usually present with enlarging or recurrent hydrocele, or less frequen...
Twinkling artifact is seen with color flow Doppler ultrasound 1. It occurs as a focus of alternating colors on Doppler signal behind a reflective object (such as a calculus), which gives the appearance of turbulent blood flow 2. It appears with or without an associated color comet-tail artifact ...
The Testicular Workup for Ischemia and Suspected Torsion (TWIST) score is a clinical decision tool used for the workup and management of acute scrotal emergencies where torsion is suspected. It uses history and examination to estimate the likelihood of torsion. Currently, validation of the clini...
An umbilical-urachal sinus belongs to the spectrum of congenital urachal anomalies and represents a non-communicating dilatation of the urachus at the umbilical end.
Presentation is commoner in children and rare in adult.
An umbilical-urachal sinus...
The umbilicus is the fibrous remnant of the fetal attachment of the umbilical cord after birth.
All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the st...
Unilateral renal enlargement can arise from a number of causes which include:
duplicated pelvicalyceal system
crossed-fused renal ectopia
renal arterial infarction
renal vein thrombosis
anatomic compression of the renal vein
The differential diagnosis for unilateral testicular lesions is wide-ranging.
seminoma (40-50% of testicular malignancies)
non-seminomatous germ cell tumors:
testicular epidermoid (teratoma with ectodermal elements only)
Urachal cysts are one of the manifestations of the spectrum of congenital urachal remnant abnormalities.
An infected urachal cyst can occur at any age.
Urachal cysts usually remain asymptomatic until complicated by infection or bleeding.
The urachus (plural: urachuses or urachi ref) is the fibrous vestigial remnant of the embryonic allantois.
The lumen of the urachus usually obliterates after birth and it becomes known as the median umbilical ligament, which is covered by a midline linear fibrous fold of parietal peritoneum (ca...
The ureter is a paired fibromuscular tube that conveys urine from the kidneys in the abdomen to the bladder in the pelvis.
The ureter is 25-30 cm long and has three parts:
abdominal ureter: from the renal pelvis to the pelvic brim
pelvic ureter: from the pelvic brim to the bla...
Ureteral calcification refers to the presence of calcium concretions within the ureteral lumen or wall.
transitional cell carcinoma
schistosomiasis of the urinary tract
Ureteral duplication is the most common congenital abnormality associated with the urinary tract, and occurs in ~1% of the population.
Duplication can occur unilaterally or bilaterally, and may be partial or complete:
partially duplicated ureters fuse into a single ureter proxim...
Ureteral pseudodiverticulosis are acquired false diverticula resulting from herniation of epithelium through the muscularis layer of the ureter and characterized by the presence of multiple outpouchings smaller than 5 mm. It is sometimes bilateral and is often located in the upper two-thirds of ...
A number of tumors may affect the ureter, by far the most common histology being transitional cell carcinoma.
transitional cell carcinoma of the ureter: 95% 1
squamous cell carcinoma of the ureter: 5%
adenocarcinoma of the ureter: <1%
The ureteric bud (also known as the metanephrogenic diverticulum) is a protrusion of the mesonephric duct that appears during the embryological development of urogenital organs. It will eventually form the urinary collecting system (i.e. collecting tubes, calyces, renal pelvis, ureter) of the ki...
Ureteric calculi or stones are those lying within the ureter, at any point from the ureteropelvic junction (UPJ) to the vesicoureteric junction (VUJ). They are the classic cause of renal colic-type abdominal pain. They are a subtype of the broader pathology of urolithiasis.
Ureteric injury is a relatively uncommon, but severe event, which may result in serious complications as a diagnosis is often delayed.
Ureteric injuries unreliably demonstrate macro- or micro-scopic hematuria as it may be absent in up to 25% of patients 5, 6. Classic cli...
Ureteric jets (or ureteral jets) are the visualization of the normal physiological periodic efflux of urine from the distal end of each ureter into the bladder.
When the urine passing down the ureter reaches the vesicoureteric junction (VUJ), it is forced out into the bladder via a ...
Ureteric rupture is rare but has been described. It may be spontaneous or secondary to another pathology or intervention.
The most common symptoms are sudden, severe, persistent lower abdominal pain with severe peritoneal irritation. Abdominal compartment syndrome, respir...
Ureteric stents, also known as double J stents, JJ stents or retrograde ureteric stents, are urological catheters that have two "J-shaped" (curled) ends, where one is anchored in the renal pelvis and the other inside the bladder.
Stents are used for the free passage of urine from the kidney to ...
Ureteritis refers to inflammation of the ureter, it is rare and is often associated with cystitis or pyelonephritis 1.
Patients may present with symptoms of cystitis or pyelonephritis with suprapubic/flank pain, dysuria, hematuria and/or fever. White cell count may also ...
Ureteritis cystica or pyeloureteritis cystica is a benign condition of the ureters representing multiple small submucosal cysts.
Typically, this condition is seen in diabetics with recurrent urinary tract infections. As such, it is most frequently seen in older patients and is mo...
Ureteroceles represent abnormal congenital dilatation of the distal-most portion of the ureter. The dilated portion of the ureter may herniate into the bladder secondary to the abnormal structure of vesicoureteric junction (VUJ).
A ureterocele occurs in about 1 in 5000 to 1 in 120...
Ureterovaginal fistulae refer to abnormal communications between the lumina of the ureter(s) and the vagina.
Patients usually present with urinary incontinence through the vagina which may be accompanied by fever and chills 1. Symptoms usually begin within 2-4 weeks foll...
The urethra is the terminal segment of the genitourinary system. Because of vastly different anatomy between the sexes, male and female urethras are discussed separately:
NB: At present (2020) there is no standardized universal terminology for the post-operative ur...
Urethral agenesis (or urethral atresia) refers to a situation where there is a congenital absence of the urethra. It can be a cause of fetal obstructive uropathy.
prune belly syndrome 5
bladder agenesis 2
May show a dilate...