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Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,010 results found
Article

Urethra

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: female urethra male urethra NB: At present (2020) there is no standardized universal terminology for the post-operative ur...
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Urethral agenesis

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. Pathology Associations prune belly syndrome 5 bladder agenesis 2 Radiographic features Antenatal ultrasound May show a dilate...
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Urethral calculus

Urethral calculi are an uncommon type of urolithiasis, accounting for ~1% of all urinary tract stones. Epidemiology They almost all occur in males 2 with two peak incidences - one in childhood and the other at 40 years 3. Clinical presentation Most commonly acute lower urinary tract symptoms...
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Urethral caruncle

Urethral caruncles are the most common urethral lesion in postmenopausal women. Epidemiology The lesion accounts for >90% of urethral masses in postmenopausal women 2. Clinical presentation Most women are asymptomatic, but caruncles can cause pain, dysuria or bleeding 4. On physical examinat...
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Urethral clamps

Various radiological and surgical instruments, including urethral clamps, have been developed to try to improve retrograde/ascending urethrogram (RUG/ASU) and voiding cystourethrogram (VCUG) technique in males. These are very rarely (if ever) used anymore. Brodny clamp This device has a metall...
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Urethral diverticulum

Urethral diverticula, or urethroceles, are focal outpouchings of the urethra. They should not be confused with a ureterocele of the distal ureter. Epidemiology Urethral diverticula occur far more frequently in women than in men and are estimated to occur in 1-6% of women, especially those with...
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Urethral diverticulum adenocarcinoma

Urethral diverticulum adenocarcinoma is a rare occurrence in a urethral diverticulum. Epidemiology Urethral diverticulum seen in ~0.6-6% of women. In small series, only 3-6% of resected urethral diverticula show adenocarcinoma 3-4. Clinical features Urinary frequency, urgency, burning mictur...
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Urethral duplication

Urethral duplication is a rare condition in which either a part of the entire urethra is duplicated. It usually occurs in the sagittal plane and the more dorsal copy is usually the duplication. Pathology A urethral duplication may occur due to a variety of developmental miscues. In a woman, it...
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Urethral glands of Littré

The urethral glands of Littré, often shortened to just the glands of Littré, and also known as the glands of Morgagni or intramural glands of the urethra, (TA: glandulae urethrales masculinae) are small glands located in the mucosa of the anterior male urethra which secrete mucus. Terminology ...
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Urethral injury

Urethral injuries can result in long-term morbidity and most commonly result from trauma. The male urethra is much more commonly injured than the female urethra and is the focus of this article. Clinical presentation In the setting of trauma, the classic triad of blood of the external urethral...
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Urethral stricture

Urethral strictures are relatively common and typically occur either in the setting of trauma or infection. Epidemiology The demographics of the affected population is dictated by the etiology, but in general, it is safe to say that adult males make up the vast majority of cases. Clinical pre...
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Urethrography

Urethrography refers to the radiographic study of the urethra using iodinated contrast media and is generally carried out in males. Terminology When the urethra is studied with instillation of contrast into the distal/anterior urethra it has been referred to as: retrograde urethrography (RUG)...
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Urinary bladder

The urinary bladder (more commonly just called the bladder) is a distal part of the urinary tract and is an extraperitoneal structure located in the true pelvis. Its primary function is as a reservoir for urine.  Gross anatomy The bladder has a triangular shape with a posterior base (a.k.a. fu...
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Urinary bladder diverticula (causes)

There are numerous causes of urinary bladder diverticula:  Primary (congenital or idiopathic) Hutch diverticulum (in paraureteral region) Secondary bladder outlet obstruction bladder neck stenosis neurogenic bladder posterior urethral valve prostatic enlargement (hypertrophy; carcinoma) ...
Article

Urinary bladder diverticulum

A urinary bladder diverticulum (plural: diverticula) is an outpouching from the bladder wall, whereby mucosa herniates through the bladder wall. It may be solitary or multiple in nature and can vary considerably in size. Epidemiology There are two peaks; one at 10 years and the other at 60-70 ...
Article

Urinary bladder hernia

Herniation of the urinary bladder is a relatively uncommon but not a rare condition. It occurs when the urinary bladder or ureter herniates into the inguinal canal, scrotal sac or femoral canal. Herniations through ischiorectal, obturator, or abdominal wall openings have also been described. Bla...
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Urinary bladder rupture

Urinary bladder rupture is usually seen in the context of significant trauma. Pathology Etiology Bladder rupture can be categorized into five types depending on the location and extent of the rupture: Bladder contusion This is commonly seen but sometimes not classed as true rupture, since i...
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Urinary bladder wall or lumen calcification (differential)

Causes of urinary bladder wall or lumen calcification include: Common bladder calculus schistosomiasis of the urinary tract tuberculosis Uncommon neuroblastoma; pheochromocytoma radiation reaction alkaptonuria (ochronosis) amyloidosis calculus in a urachal cyst or in a bladder divertic...
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Urinary diversion

Urinary diversion is created after the removal of the urinary bladder (radical cystectomy or cystoprostatectomy, usually done to treat invasive bladder cancer). There are three main varieties: neobladder formed from a segment of ileum (i.e. ileal conduit, also known as a "Bricker conduit") th...
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Urinary system

The urinary system consists of the kidneys, ureter, bladder and urethra. With the exception of the urethra, this is the same in both males and females.  It spans the abdomen and pelvis, from the upper abdomen to the extreme pelvis, being inextricably linked with the genital system. The urinary ...
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Urinary tract dilatation classification

The urinary tract dilatation (UTD) classification system is a proposed unified classification of urinary tract dilatation for prenatal and postnatal care. This classification was formed with the collaborations from eight societies (American College of Radiology (ACR), American Institute of Ultra...
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Urinary tract infection

Urinary tract infection (UTI) is a common clinical condition involving the bladder (cystitis) and kidneys (pyelonephritis). It is commonly divided into 'uncomplicated' and 'complicated' infections.  Clinical presentation painful urination strangury bloody, dark, cloudy urine urinary frequen...
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Urine

Urine represents the biofluid end-product of the renal filtration process. Normally it is a transparent, sterile, pale-yellow liquid (although clearly color varies with the person's hydration status).  Urine is one of the most easily-accessible biofluids in the human body and has been intensive...
Article

Urinoma

Urinomas, or uriniferous fluid collections, are urine collections usually found in the retroperitoneum, most commonly in the perirenal space, as a consequence of renal tract leakage caused by urinary obstruction, trauma, or post-instrumentation.  Terminology As there is no definitive distincti...
Article

Urinothorax

Urinothorax (plural: urinothoraces), also known as urothorax, is a rare cause of pleural effusion due to the accumulation of urine within the pleural space. Clinical presentation Patients present with varying degrees of respiratory distress depending on the amount of fluid that has accumulated...
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Urogenital curriculum

The urogenital curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core genitourinary knowledge. Definition  Topics pertaining to the urinary tract (kidneys, ureter, bladder, urethra), adrenal glands, prostate penis, scrotal content (testes, ...
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Urogenital diaphragm

The urogenital diaphragm is an incorrect historic term describing a structure or structures in the perineum. The term is still in occasional use despite not appearing in Terminologia Anatomica. Most descriptions of the diaphragm relate to a discoid space between the superficial and deep fasciae...
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Urogenital triangle

The urogenital triangle forms the anterior half of the diamond-shaped perineum. The triangle's corners are defined by the pubis symphysis anteriorly and the ischial tuberosities anterolaterally. The anterolateral borders are the ischiopubic rami and the posterior border is the transverse perinea...
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Urolithiasis

Urolithiasis refers to the presence of calculi anywhere along the course of the urinary tracts. For the purpose of the article, the terms urolithiasis, nephrolithiasis, and renal/kidney stones are used interchangeably, although some authors have slightly varying definitions of each.  See main a...
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Urothelial carcinoma of the prostate

Urothelial carcinomas or transitional cell carcinomas of the prostate are malignant neoplasms that can occur as primary cancers of the prostate gland. Epidemiology Prostatic urothelial carcinomas account for less than 2-4% of all prostate cancers 1 and are usually seen in middle-aged men 2. A...
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Urothelial carcinoma with squamous differentiation

Urothelial carcinoma with squamous differentiation (USCD) is a variation of urothelial cell carcinoma which is associated with advanced tumor stage. When occurring in relation to bladder cancer, around 60-70% of the cases occur in those with muscle-invasive bladder cancer (MIBC) 1. Treatment an...
Article

Urothelial cell carcinoma (urethra)

Urothelial cell carcinoma of the urethra (formerly transitional cell carcinoma) is rare and is almost always limited to the proximal urethra in men (membranous and prostatic). The vast majority of urethral malignancies are squamous cell carcinomas. This article concerns itself with transitional...
Article

US abdomen (summary)

This is a basic article for medical students and other non-radiologists Ultrasound abdomen is one of the tests that is commonly used in the assessment of patients with abdominal pain. It is particularly useful for the assessment of solid organs and fluid-filled structures. Reference article T...
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Utricle (disambiguation)

The utricle may refer to: utricle of the inner ear utricle of the prostatic urethra
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Uvula (disambiguation)

The uvula (plural: uvulae or uvulas) may refer to several different anatomical structures. When used as a standalone term it is usually understood to refer to the soft palate uvula. uvula (soft palate) uvula (cerebellum) uvula (male bladder) History and etymology Uvula is Latin for 'little ...
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Vaginal artery

The vaginal artery is a branch of the anterior division of the internal iliac artery, and should not to be mistaken with the vaginal branch of the uterine artery. It is often considered to be a homolog of the inferior vesical artery, which is present only in males. Summary origin: anterior div...
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Vaginal opening

The vaginal opening, is also known as the introitus (plural: introituses), vaginal orifice, or ostium vaginae (plural: ostia vaginarum) (TA) . Gross anatomy The entrance to the vagina lies in the vestibule of the vulva in the median plane. It has an anteroposterior orientation and is partially...
Article

Valsalva maneuver

The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic, and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly u...
Article

Varicocele

Varicocele is the dilatation of the pampiniform plexus of veins, a network of many small veins found in the male spermatic cord. It is the most frequently encountered mass of the spermatic cord. Epidemiology The estimated incidence is at ~15% of the general male population and ~40% of subferti...
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Varicocele embolization

Varicocele embolization is a minimally invasive method of treating varicoceles by embolizing the testicular vein (internal spermatic veins). Indications symptomatic varicocele infertility/subfertility failed surgical ligation Contraindications Relative contraindications include: intraveno...
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Varicocele grading on color Doppler

Varicocele grading on color Doppler can be done variably. The most elaborate and widely-accepted grading was given by Sarteschi, as below.  For a general discussion of this condition refer to the article: varicocele. Evaluation baseline greyscale study in supine position and measure the diame...
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Vasitis

Vasitis (plural: vasitides), also known as deferentitis (plural: deferentitides) 7, is an uncommon inflammatory disorder of the vas deferens and spermatic cord. It is classified as either the generally asymptomatic vasitis nodosa (seen after vasectomy) or acutely painful infectious vasitis. This...
Article

Venous intravasation

Venous intravasation is the unintended introduction of radiographic contrast material into the local venous system. It is a well-recognized phenomenon during retrograde urethrograms 1,2 and hysterosalpingograms (HSG), although can occur with other invasive procedures in the vicinity of venous pl...
Article

Verumontanum

The verumontanum or seminal colliculus is the rounded eminence of the urethral crest within the posterior wall of the mid prostatic urethra. The prostatic utricle opens into it in the midline and the two ejaculatory ducts open just distal to the utricle. On either side of it lie the prostatic si...
Article

Vesical Imaging-Reporting and Data System (VI-RADS)

The Vesical Imaging–Reporting and Data System (VI-RADS) is a structured reporting scheme for multiparametric bladder MRI in the evaluation of suspected bladder cancer. A systematic approach to bladder lesion based on multiparametric MRI (mpMRI) was proposed by the European Association of Urology...
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Vesicourachal diverticulum

Vesicourachal diverticulum is one of the congenital urachal remnant abnormalities. Gross anatomy It is the proximal equivalent of a urachal umbilical sinus, representing a result of the failure of the urachus to close at the urinary bladder, forming an out-pouching of variable length from the ...
Article

Vesicoureteric junction

The vesicoureteric junction (VUJ), also known as the ureterovesicular junction (UVJ) is the most distal portion of the ureter, at the point where it connects to the urinary bladder.  Terminology Traditionally it is called the vesicoureteric junction, however some anatomists, radiologists and o...
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Vesicoureteric reflux

Vesicoureteric reflux (VUR) is the term for the abnormal flow of urine from the bladder into the upper urinary tract and is typically encountered in young children. For grading of vesicoureteric reflux, please refer to vesicoureteric reflux grading. Epidemiology The incidence of urinary tract...
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Vesicoureteric reflux (grading)

Vesicoureteric reflux (VUR) grading divides vesicoureteric reflux (VUR) according to the height of reflux up the ureters and degree of dilatation of the ureters: grade 1: reflux limited to the ureter grade 2: reflux up to the renal pelvis grade 3: mild dilatation of ureter and pelvicalyceal s...
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Vesicovaginal fistula

Vesicovaginal fistulas are abnormal fistulous connections between the urinary bladder and vagina, resulting in an involuntary discharge of urine through the vagina. Epidemiology The overall incidence of vesicovaginal fistula is unknown but was reported to be 2.11 per 100 births in Nigeria 1. ...
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Vesicovaginal reflux

Vesicovaginal reflux is a well-known entity rarely encountered by radiologists. It is a behavioral disorder, a type of dysfunctional elimination syndrome commonly encountered in pre-pubertal girls. It is defined as reflux of urine into the vaginal vault either in supine or upright position durin...
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Vestibule of the vulva

The vestibule of the vulva (vestibule of the vagina in some texts 2) is the area between the labia minora, and posterior to the glans of the clitoris. It marks the boundary between the vagina and the vulva. The urethra, vagina and the greater vestibular glands open out into the vestibule.
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Vicarious contrast media excretion

Vicarious contrast media excretion (VCME) is defined as excretion of intravascularly-administered water-soluble contrast media in a way other than via normal renal excretion. The most common vicarious excretion of water-soluble contrast material is via the liver, resulting in increased bile dens...
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Viscera

The viscera (singular: viscus) refers to all the internal organs within the major cavities of the thorax, abdomen and pelvis. Therefore it does not include organs of the CNS, head and neck or musculoskeletal compartments nor does it encompass non-internal organs (e.g. the skin) 1. Splanchnology...
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Voiding cystourethrography

Voiding cystourethrography (VCUG), also known as a micturating cystourethrography (MCU),  is a fluoroscopic study of the lower urinary tract in which contrast is introduced into the bladder via a catheter. The purpose of the examination is to assess the bladder, urethra, postoperative anatomy an...
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Von Hippel-Lindau disease

Von Hippel-Lindau (vHL) disease is characterized by the development of numerous benign and malignant tumors in different organs (at least 40 types 1) due to mutations in the VHL tumor suppressor gene on chromosome 3. Epidemiology The disease is rare with an estimated prevalence of 1:35,000-50,...
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Vulva

The vulva (plurals: vulvas or vulvae), also known as the pudendum, (plural: pudenda) is the collective term given to the female external genitalia. The vulva consists of the: mons pubis labia majora labia minora clitoris bulbs of the vestibule vestibule of the vulva vaginal opening hyme...
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Vulval varices

Vulvar varices are dilated superficial veins of the external female genitalia, which are primarily seen during pregnancy and usually resolve spontaneously postpartum. Epidemiology Vulvar varicosities are seen in up to 4% of pregnant females in the vulvar and perivulvar region, and rarely seen ...
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WAGR syndrome

The WAGR syndrome or complex stands for: Wilms tumors (greatly increased risk) aniridia genitourinary anomalies intellectual retardation (disability) Pathology Genetics Occurs from a mutation related to chromosome 11p13 3 which is in close proximity to the WT1 gene.
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Waist sign hydrosalpinx

The waist sign arises from the folding of a distended tube upon itself producing indentations on diametrically opposite sides. The waist sign is specific for hydrosalpinx and virtually pathognomonic when seen in association with a tubular-shaped cystic mass. See also cogwheel sign beads on a ...
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Watchful waiting

Watchful waiting describes a palliative management option with the main goal to maintain/improve quality of life, to control of complications as well as to minimize adverse treatment-related effects. Usage Watchful waiting is usually considered in elderly patients with tumors or otherwise limi...
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Waterhouse-Friderichsen syndrome

Waterhouse-Friderichsen syndrome (also known as purpura fulminans 9 or hemorrhagic adrenalitis 10) is characterized by adrenal insufficiency that results from atraumatic adrenal hemorrhage in consequence of septicemia.  Pathology Waterhouse-Friderichsen syndrome is due to septicemia and common...
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Watering-can perineum

Watering-can perineum is the result of multiple fistulae extending from the urethra to open within the perineum. In these patients, urine can exit through these perineal openings 1,2. The fistulae can be detected with voiding cystourethrography, however, the definite cause can be determined with...
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Watermelon skin sign

The watermelon skin sign refers to diffuse, radiating, streaky areas of low signal intensity in prostate on T2WI in patients with prostatic tuberculosis 1.  
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Weigert-Meyer law

The Weigert-Meyer law describes the relationship of the upper and lower renal moieties in duplicated collecting systems to their drainage inferiorly. Weigert-Meyer law With duplex kidney and complete ureteral duplication, the upper renal and lower renal moieties are drained by separate ureters...
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Well-differentiated neuroendocrine tumor of the prostate

Well-differentiated neuroendocrine tumors of the prostate also known as low-grade neuroendocrine carcinoma of the prostate or carcinoid tumors of the prostate are low-grade neuroendocrine tumors arising from the prostate that may metastasize. Epidemiology Well-differentiated neuroendocrine tum...
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Whirlpool sign (testicular torsion)

The whirlpool sign of the spermatic cord is a direct sign of testicular torsion, both complete and incomplete (i.e. <360°). It is considered to be the most specific and sensitive sign for testicular torsion. Terminology The term whirlpool sign is used in other contexts: see whirlpool sign (dis...
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White pyramid sign (kidney)

The white pyramid sign, also known as dense renal medulla sign (DRM) or hyperdense renal pyramids sign, refers to the CT appearance of the medullary pyramids of the kidney which can be seen normally on unenhanced CT scans as high-attenuation triangular structures. Etiology incidental normal fi...
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Whitmore-Jewett staging system

Whitmore-Jewett staging system (also known as the Jewett staging system or ABCD system) is a staging system for prostate cancer. It was developed by the American Urological Association (AUA). Most societies (including AUA) and clinicians now advocate and use the TNM staging system. A: subclinic...
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WHO classification of prostate tumors

The World Health Organization (WHO) classification of prostate tumors is a commonly used classification system for prostate tumors. The current version was published in 2016 as part of the  WHO Classification of Tumors of the Urinary System and Male Genital Organs 1,2 and replaces the previous c...
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WHO classification of tumors of the kidney

The World Health Organization (WHO) classification of tumors of the kidney is the most commonly used pathologic classification system for such disorders. The current revision, part of the 4th edition of the WHO series, was published in 2016 as part of the WHO Classification of Tumors of the Urin...
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WHO histological classification of benign renal neoplasms

Benign renal tumors were histologically classified according to the World Health Organization 1. This is the subset of entities in the 2016 WHO classification of renal tumors that are associated with an International Classification of Diseases for Oncology (ICD-O) behavior code of 0, indicating ...
Article

Wilms tumor

Wilms tumor, also known as nephroblastoma, is a malignant pediatric renal tumor. Epidemiology Wilms tumors are the most common pediatric renal mass, accounting for over 85% of cases 1,8 and account for 7% of all childhood cancers 12. It typically occurs in early childhood (1-11 years) with pea...
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Wilms tumor (staging)

Wilms' tumor staging is largely anatomical and relates to the invasion and spread of the tumor. Where there is invasion or metastasizes, prognosis is poorer. Wilms tumor, is one of the more common childhood malignancies. stage I confined to kidney complete resection possible stage II local ...
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Wolffian duct

The Wolffian duct (also known as the mesonephric duct) is one of the paired embryogenic tubules that drain the primitive kidney (mesonephros) to the cloaca. It also gives off a lateral branch forming the ureteric bud. In both the male and the female, the Wolffian duct develops into the trigone o...
Article

Wunderlich syndrome

Wunderlich syndrome is a rare condition in which spontaneous non-traumatic renal hemorrhage occurs into the subcapsular and perirenal spaces. Clinical presentation Wunderlich syndrome is clinically characterized by Lenk's triad: acute flank pain flank mass hypovolemic shock ​Mnemonic F: f...
Article

Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis (XGP) is a rare form of chronic pyelonephritis and represents a chronic granulomatous disease resulting in a non-functioning kidney. Radiographic features are usually specific. Epidemiology Xanthogranulomatous pyelonephritis is seen essentially in all age gro...
Article

Young syndrome

Young syndrome shares similar clinical and radiological findings to primary ciliary dyskinesia and cystic fibrosis, however, the underlying pathogenesis is yet to be fully elucidated. Obstructive azoospermia at the level of the epididymis is thought to be the cause of infertility. The commonly r...
Article

Yo-yo reflux

Yo-yo reflux or uretero-ureteral reflux is noted in partial duplication of ureters 1,2. It is the reflux of urine from normal caliber ureter to dilated ureter.  Radiographic features Yo-yo reflux should be suspected when there is asymmetric dilatation of ureters. It can be diagnosed with color...
Article

Zinner syndrome

Zinner syndrome is a triad of mesonephric (Wolffian) duct anomalies comprising unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction 1. Clinical presentation Patients are typically diagnosed during the 3rd or 4th decade of life and often present with per...

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