Ectopic testes are a rare congenital anomaly, differing from undescended testis (cryptorchidism) in that ectopic testis is a congenitally abnormally located testis, that has descended from the abdominal cavity away from the normal path of descent while undescended testis are congenitally abnorma...
An ectopic ureter is a congenital renal anomaly that occurs as a result of abnormal caudal migration of the ureteral bud during its insertion to the urinary bladder. Normally the ureter drains via the internal ureteral orifice at the trigone of the urinary bladder.
In females, the most common ...
The ejaculatory ducts are paired structures of the male reproductive system and convey seminal fluid.
Each ejaculatory duct is formed by the union of the excretory duct of the seminal vesicle and the ampulla of the ductus deferens, and is approximately 2 cm long. The ducts course...
Ejaculatory duct cysts are a rare type of cyst of the prostate gland.
They occur due to obstruction of the ejaculatory duct which in turn can either be congenital or secondary (e.g. inflammation).
They are usually intraprostatic when small but may extend cephalad when large.
A useful mnemonic to remember the ejaculatory pathway of sperm is:
S: seminiferous tubules of the testes
V: vas (ductus) deferens
E: ejaculatory duct
Emphysematous cystitis (EC) refers to gas-forming infection of the bladder wall.
The condition is rare and usually confined to certain patient subgroups.
Risk factors include:
considered the commonest predisposing factor 6
may be present in ~50%...
Emphysematous epididymo-orchitis is a rarely reported entity with only a handful of case reports which still lacks a strong evidence for the existence of the disease. It is reported as a rare cause of acute scrotum encountered in poorly controlled diabetics. Pathology of this condition is unknow...
Emphysematous prostatitis refers to gas-forming infection of the prostate, nearly always occurring concurrently with prostatic abscess.
The condition is rare, most commonly presenting in males aged 50-70 years and usually confined to certain patient subgroups 1,2.
Emphysematous pyelitis is isolated gas production inside the excretory system, secondary to acute bacterial infection. It is a relatively benign entity and needs accurate differentiation from the far more serious emphysematous pyelonephritis, which is gas production from an infection in the rena...
Emphysematous pyelonephritis refers to a morbid infection of kidneys, with characteristic gas formation within or around the kidneys. If not treated early, it may lead to fulminant sepsis and carries a high mortality.
The patient usually presents with flank pain, urinary ...
Empyemas are purulent inflammatory collections within a body cavity. They are similar to abscesses, which arise within parenchymal tissue rather than occupying a pre-existing anatomical space.
Colloquially, the term empyema is used to refer to thoracic empyemas but there are variou...
Endometrial carcinoma staging allows appropriate treatment options to be considered and enables greater prognostic accuracy for endometrial carcinoma.
Staging can be based on the TNM or FIGO system.
MR imaging is the modality of choice for staging with CT having relatively low speci...
End-stage kidney disease (ESKD), also referred as end-stage renal failure, corresponds to the last stage of a chronic kidney disease (stage 5), when the kidneys function is no longer sufficient to sustain life (GFR <15) and kidney replacement therapy (dialysis or transplant) is required.
Eosinophilic ureteritis (and eosinophilic pyelouerteritis) is a rare cause of ureteral inflammation. The clinical presentation and imaging features are non-specific.
Patients are usually atopic or hypereosinophilic with peripheral eosinophilia.
Associated with eosinophil...
The term epidermoid cyst can refer to a:
epidermal inclusion cyst
intracranial epidermoid cyst
splenic epidermoid cyst
spinal epidermoid cyst
testicular epidermoid cyst
An epididymal abscess is an uncommon complication of epididymitis.
Causative organisms are the same that cause epididymitis:
Other rare aetiological agents
Epididymal appendices, also known as appendix of the epididymis or appendix epididymis, are an testicular appendage found at the head of the epididymis 1. They represent a developmental remnant of the mesonephric duct (Wolffian duct). In 78% of the cases, it has a stalk configuration and is thus...
Epididymal calcification can be seen on ultrasound as hyperechoic foci within the epididymal head. If the calcifications are large enough, then they may demonstrate acoustic shadowing.
chronic epididymitis: e.g. bacterial, granulomatous (TB) or genital filariasis
Epididymal cysts are the most common epididymal mass.
Epididymal cysts have been reported in ~30% (range 20-40%) of asymptomatic individuals 5.
They are usually of lymphatic origin 2. The cysts contain clear serous fluid, lymphocytes, spermatozoa and debris.
Epididymal masses are most commonly encountered on ultrasonography. Most epididymal masses are benign; malignant lesions are rare.
adenomatoid tumor of the scrotum (most common epididymal mass 4)
sperm granulomas / post vasectomy gran...
The epididymis (plural epididymides) is situated adjacent to the testis within the scrotal sac. Its primary function is the collection, maturation and transport of sperm via the ductus deferens.
The epididymis is an elongated structure, posterolateral to the testis. It can be sub...
Epididymitis refers to inflammation of the epididymis, and may be associated with inflammation extending to the testis itself, in which case the term epididymo-orchitis is used. This should be distinguished from isolated orchitis, which is by comparison much less common.
Epispadias is a rare congenital anomaly that is almost always associated with bladder exstrophy.
It occurs in 1 in 30,000 births, with a male: female ratio of 3:1.
The roof of the urethra is absent and the urethra opens anywhere between the base and the gl...
Epithelioid angiomyolipomas (EAML) are rare variants of the more common renal angiomyolipoma. They have malignant potential.
Like more common renal angiomyolipomas, EAMLs are considered perivascular epithelioid cell tumors (PEComas). EAMLs were regarded as a separate renal mass entit...
The erased charcoal sign describes the typical appearance of focal prostate cancer in the transition zone characterized as homogeneous hypointensity on T2WI with ill-defined borders, akin to a charcoal pencil drawing smudged with an eraser, often with a lenticular or waterdrop-like shape.
The external iliac lymph nodes can be found surrounding the external iliac artery and act as the draining nodes for several regions of the pelvis and lower limb.
The external iliac lymph nodes lie anterior to the internal iliac lymph nodes and usually form three separate subgrou...
Multiple criteria are used to detect extracapsular extension of prostate cancer. They include 3:
an irregular bulge in capsule
obliteration of the rectoprostatic angle
asymmetry of the neurovascular bundle
angulation/step-off appearance to the tumor
focal capsular retraction and or thickeni...
Extracorporeal shock wave lithotripsy (ESWL) is a common non-invasive treatment for urolithiasis. It is less successful in obese patients and with stones >2 cm.
steinstrasse: incomplete fragmentation that results in a pile-up of stone fragments that obstruct the ureter
Extrapulmonary tuberculosis (TB) refers to the haematogenous spread of Mycobacterium tuberculosis.
Extrapulmonary tubercuosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can ...
Extrarenal pelvis refers to the presence of the renal pelvis outside the confines of the renal hilum; it is a normal anatomic variant.
It is found in ~10% of the population 2.
An extrarenal pelvis usually appears dilated, erroneously suggesting...
The differential diagnosis for extratesticular cystic lesions includes:
loop of bowel from an inguinal hernia
Very rarely, a scrotal mesothelioma may present as a cystic mass.
Extratesticular scrotal masses (non-testicle and non-epididymis) are mostly mesenchymal in origin and benign 1.
lipoma (most common)
leiomyoma of the scrotum
granular cell tumor
fibrous hamartoma of infancy...
A faceless kidney refers to one in which the normal appearance of the renal sinus on cross-sectional imaging is absent. It was initially described as a sign of duplication of the collecting system 1 (a slice obtained between the two collecting systems will not demonstrate the normal components o...
Fanconi syndrome describes generalised proximal renal tubule dysfunction causing impaired reabsorption of many urinary solutes.
Clinical features include poor growth, fatigue, dehydration, polyuria, muscle weakness, and bone pain. Features on a basic blood panel includes...
There are numerous fat-containing renal lesions, including:
renal cell carcinoma
renal or perirenal lipoma/liposarcoma
Non-mass lesions may also occasionally contain fat:
renal junction line
fat in a renal scar
renal sinus lipomatosis
Female prostate sign is a characteristic imaging sign seen in patients with a large urethral diverticulum.
A large urethral diverticulum in females surrounds the urethra, and elevates the base of the bladder, mimicking the typical appearance of enlarged prostate in males.
Female pseudohermaphroditism (FPH) is a form of disorder of gender development.
Patients with female pseudohermaphroditism have female internal genitalia and female karyotype (XX) with various degree of external genitalia virilization.
congenital adrenal hyperplasia (CAH) ...
The female urethra is a simple short tube, that transports the urine out of the body, extending from the internal urethral orifice of the bladder to the external urethral orifice in the vestibule of the vagina.
The female urethra measures approximately 4 cm in length. It is embe...
Fetal cystic renal disease can be in included in three of the four types classified according the system by Osathanondh and Potter 1:
Potter type I: infantile polycystic kidney disease
Potter type II: multicystic dysplastic kidneys
Potter type III: adult polycystic kidney disease
A fetal hydrocele refers to a hydrocele present in utero.
They may be sonographically identified in ~15% of male fetuses in the third trimester 6.
Often result from a patent processus vaginalis. They are more frequently unilateral.
Fetal hydronephrosis represents the abnormal dilatation of the fetal renal collecting system, with pelviureteric junction obstruction the most commonly encountered cause.
Please, refer to the article on fetal pyelectasis for a dedicated discussion on this relatively common and usually benign f...
Fetal megacystis refers to the presence of an unusually large bladder in a fetus.
The estimated incidence of antenatal imaging is at ~1:1500 pregnancies.
It can result from a number of causes but the main underlying mechanism is either a distal stenosis or reflux.
Fetal pyelectasis refers to a prominence of the renal pelvis in utero that is a relatively common finding, which in the majority of cases resolves spontaneously.
Please refer to the article on fetal hydronephrosis for a continued discussion on this matter.
Although there is an ...
A fetal urachal cyst refers to a urachal cyst occuring in utero. It may or may not communicate with the vertex of the fetal bladder. It may also arise within the umbilical cord. Umbilical cord urachal cysts originate from an extra-abdominal urachal system.
fetal intra-abdominal cysts...
Fetal urinary ascites is one of the causes of fetal ascites and can arise from a number of pathologies.
in utero bladder perforation
transudation from the fetal bladder
persistent urogenital sinus
The presence of fetal ascites without...
Fibromuscular dysplasia (FMD) is a heterogeneous group of vascular lesions characterized by an idiopathic, non-inflammatory, and non-atherosclerotic angiopathy of small and medium-sized arteries.
The prevalence is unknown 7. It is most common in young women with a female to male r...
Fibrous pseudotumour of the scrotum is a relatively rare, non-neoplastic extratesticular non-epididymal lesion.
It affects any age. Although rare, it is considered the third most common extra testicular mass after a scrotal lipoma and an epididymal adenomatoid tumor.
The filarial dance sign refers to a twirling motion of microfilariae (e.g. W. bancrofti) noted in dilated lymphatic channels. It is identified as a characteristic sign and indicator of scrotal filariasis.
The dilated channels are identified with absence of color flow on color Doppler study (CDS...
Filariasis refers to infection with nematodes (roundworms) of the family Filarioidea. There are three species of these thread-like filarial worms:
Wuchereria bancrofti: responsible for 90% of cases
Brugia malayi: causes most of the remainder of cases
Brugia timori: an uncommon cause
It can a...
The Finnish type congenital nephrotic syndrome is a sub type of congenital nephrotic syndrome. A large placenta and proteinuria from birth are considered hallmarks of the disease 2. The proteinuria is often of intra-uterine onset. Although it is named the Finnish type, it can occur outside Finla...
Fishhook ureters, also known as J-shaped ureters or hockey stick ureters describe the appearance of the distal ureter in patients with significant benign prostatic hypertrophy. It has also been used to describe the appearance of a retrocaval ureter in type 1 or low loop variety. As the right ur...
Fluorine-18-labeled sodium fluoride (also known as 18F-NaF or sodium fluoride) is a PET radiotracer used primarily for skeletal imaging.
Fluorine-18-labeled sodium fluoride is an ionic compound comprised of a single sodium atom bound to a positron-emitting isotope of fluorine.
The Foley catheter is a urinary catheter with a balloon at its distal tip, which is inflated post-insertion to ensure that the catheter remains in the bladder. Originally inflation of the balloon required the instillation of fluid or air via a separate port, next to the external end of the cathe...
Folliculin gene-associated syndrome (FLCN-S) or Birt-Hogg-Dubé (BHD) syndrome is a genetic multisystemic disease mainly characterized by:
multiple lung cysts and secondary spontaneous pneumothoraces
multiple bilateral renal tumors (particularly chromophobe renal cell cancer and oncocytoma)
The term fornix (plural: fornices) is used for anatomical structures in multiple organ systems that all share an arch-like morphology:
History and etymology
Fornix is Latin for...
The fossa navicularis refers to a normal mild dilatation of the urethra. It occurs at the most distal/downstream portion of the urethra.
It is more evident in males, where it occurs in the penile/pendulous urethra, near the urethral meatus. There is also a fossa navicularis in women: the more f...
The fountain sign is sonographic sign described in acute idiopathic scrotal edema (AISE).
It refers to the appearance of the pattern of vascularity seen during transverse color Doppler sonography of the scrotum with both testes together1. In these transverse views in patients with AISE, marked ...
Fournier gangrene is a necrotizing fasciitis of the perineum. It is a true urological emergency due to the high mortality rate but fortunately, the condition is rare.
Fournier gangrene is typically seen in diabetic men aged 50-70 years but rarely in women. Other than age, predispo...
Fraley syndrome is the eponymous term for a dilated calyx (hydrocalyx) due to compression of a calyceal infundibulum from an adjacent artery or vein. It is rare, but it occurs more often in an upper pole calyx. The hydrocalyx may be painful.
The free/total PSA ratio (%fPSA) is an additional new parameter used in assessing PSA levels. Some authors 1,2 recommend that men with PSA levels of 4.1 to 10 ng/mL who are not suspected of having prostate cancer by whatever means should undergo %fPSA measurement and then be carefully monitored ...
Frenulum (plural: frenula) is an anatomical term and refers to a small fold of soft tissue that checks the movement of an anatomical part.
frenulum (ileocecal valve)
frenulum (labia minora)
History and etymology
Frenulum derives from ...
Fungal balls of the urinary tract, also known as fungal bezoars or mycetomas of the urinary tract, are a rare manifestation of funguria, usually candiduria.
While candiduria may be seen in approximately 20% of hospitalised patients 1, development of fungal balls is considered very...
Ganglioneuromas are fully differentiated neuronal tumors that do not contain immature elements and potentially occur anywhere along the peripheral autonomic ganglion sites.
On imaging, usually, they present as well-defined solid masses and can be quite large at presentation. Generally, they ar...
There numerous causes of gas in the bladder. In the hospital setting by far the most common is the recent placement of an indwelling urinary catheter. Other causes include 1:
indwelling urinary catheter is by far the most common cause
Genitourinary tuberculosis is the second most common site of infection in humans by Mycobacterium tuberculosis, second only to pulmonary tuberculosis.
It can most easily be divided anatomically into:
renal tuberculosis (renal parenchyma, calyces and renal pelvis)
bladder and ureteric tubercu...
Germ cell tumors are classified into two broad groups: seminoma and non-seminomatous germ cell tumors (NSGCT). The later is then divided further according to histology.
non-seminomatous germ cell tumors (NSGCT)
yolk sac tumor...
Germ cell tumors are found widely throughout the body, and encompass a wide range of individual tumors.
This article does not deal with any specific body locations. For detailed discussion please refer the articles listed at the end of this page.
Germ cell tumors arise from ectopic...
A mnemonic for differential diagnosis for germ cell tumors is:
E: embryonal cell carcinoma
E: endodermal sinus tumor (yolk sac tumor)
Germinoma is a term that if unqualified, usually refers to a tumor of the brain but can also refer to similar tumors of other regions particularly the ovary and testis.
dysgerminoma of the ovary
seminoma of the testis
CNS germinoma: see WHO classification of CNS tumors
All these tumors share...
The histological grading of prostate cancer has undergone many revisions requiring careful distinction between the terms Gleason grade, Gleason score and Grade Group.
The Gleason grade, originally described in 1974, describes the histologic pattern of gland arrangement 2. Gleason grade patter...
The goblet sign, also known as the champagne glass sign, refers to the appearance of the ureter when it is focally dilated by an intraluminal mass. It is best seen when the ureter is opacified by retrograde contrast (retrograde ureterogram). Presence of this sign indicates the pathology to be ch...
The Goldman classification of urethral injuries is a more widely accepted classification than one proposed by the American Association for the Surgery of Trauma (AAST). The Goldman classification is based on the anatomical location of the urethral injury and was initially proposed by Colapinto a...
The gonadal arteries are the paired primary vascular supply to the ovaries in the female and the testes in the male. As the anatomy of the gonadal arteries differs substantially between the sexes, they are covered separately:
The gonadal veins are paired structures that drain the gonads in males and females. In males it is called the testicular vein (or internal spermatic vein) and in females it is called the ovarian vein. The gonadal veins ascend with the gonadal arteries in the abdomen along the psoas muscle anteri...
Gonadoblastomas are uncommon sex cord / stromal tumors. They are associated with disorders of sexual development (previously known as "intersex disorders").
The vast majority are found <30 years of age. Most are discovered in the perinatal period. May occur in phenotypic males or ...
Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem necrotizing non-caseating granulomatous c-ANCA positive vasculitis affecting small to medium sized arteries, capillaries and veins, with a predilection for the respiratory system and kidneys 3.
The renal manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener granulomatosis) are occult on imaging, especially when compared to the pulmonary changes. Approximately half of GPA patients have kidney disease at presentation. Granulomatosis with polyangiitis is a ...
Granulomatous prostatitis is a nodular form of chronic prostatitis. It is usually diagnosed on biopsy.
Several classification systems exist. A frequently used clas...
The great vessel space is the fourth retroperitoneal space along with the anterior and posterior pararenal spaces, and the perirenal space 1,2. Unlike other retroperitoneal spaces, it is not well-defined by fascial planes and thus disease processes affecting other retroperitoneal spaces can also...
Growing teratoma syndrome is a rare complication after treatment for metastatic (or in the case of intracranial disease, primary) non-seminomatous germ cell tumors (NSGCT).
It was first described in the pediatric population with treated germ cell neoplasms, and represents enlarging masses at th...
Hematospermia (less commonly hemospermia) refers to the presence of blood in semen or ejaculatory fluid. It is a symptom that can cause great anxiety in patients despite usually being of benign etiology.
urogenital infections including sexually transmitted disease, ...
Hematuria occurs when blood enters the urinary collecting system and is excreted in the urine. There are many etiologies for hematuria, and they range from benign and transient to gravely concerning. Hematuria can derive from the kidneys, ureters, bladder, prostate (in men), or urethra. Imaging ...
Hematuria in a child is evaluated differently than in an adult in two main respects:
there is a lower likelihood of a malignancy (renal or bladder) causing the hematuria
preference is given to nonionizing radiation
Hematuria can be considered in three main forms:
Hemolytic uremic syndrome (HUS) is a multisystem thrombotic microangiopathic disease characterized by the triad of renal failure, hemolytic anemia and thrombocytopenia. It is the most common cause of renal failure in infancy and childhood requiring dialysis.
There are two forms of this syndrom...
The hemorrhage exclusion sign can be a useful MRI finding following prostate biopsy.
The normal prostate produces high concentrations of citrate, which among other properties, acts as an anticoagulant 1. As tumor cells are dysfunctional, they will produce lower levels of citrate than...
The hairy kidney sign refers to the soft tissue rind of perirenal infiltration seen on cross-sectional imaging studies in Erdheim-Chester disease, and is considered to be pathognomonic of this disease. The ‘‘hairy’’ description refers to the associated thickening of the bridging perirenal septa ...
Height adjusted total kidney volume (HtTKV) is used in patients with autosomal dominant polycystic kidney disease to predict the onset of renal insufficiency. There is strong evidence to indicate that baseline htTKV predicts, with good sensitivity and specificity, the development of renal insuff...
Hepatorenal syndrome refers to a form of acute kidney injury caused by changes in renal blood flow regulation due to liver pathology 1. Although the syndrome occurs mainly in cirrhotic livers it has been reported in patients with acute fulminant liver failure as well 1.
Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant monogenic COL4A1-related disorder.
The exact prevalence is unknown.
The cardinal features of HANAC syndrome are helpfully described in the name of...
Hereditary breast and ovarian cancer (HBOC) syndrome is caused by a mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast ca...
Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a recently identified autosomal dominant tumor susceptibility syndrome.
It is characterized by:
predisposition to benign cutaneous and uterine leiomyomas (fibroids, myomas)
susceptibility to early-onset renal cell carcinoma
Despite the vast majority of renal cancers being sporadic, there are a number of hereditary renal cancer syndromes:
von Hippel Lindau syndrome: predominantly clear cell type
tuberous sclerosis: predominantly clear cell type
hereditary leiomyomata renal cell cancer syndrome: described in ISUP ...
Herlyn-Werner-Wunderlich (HWW) syndrome, is a rare anomaly characterized by Müllerian duct anomalies (MDA) associated with mesonephric duct anomalies 3. This entity is also known as obstructed hemivagina and ipsilateral renal anomaly (OHVIRA). It is not to be confused with the Wunderlich syndro...