Endometrial stromal tumours (EST) constitute <2% of all uterine tumours and <10% of uterine mesenchymal neoplasms 1.
Over the past four decades, EST classification has gone through various modifications starting from the earliest study by Norris and Taylor 2. This was primarily due to th...
The AAST (American Association for the Surgery of Trauma) renal injury scale 3-4 is the most widely used renal trauma grading system at the time of writing (mid 2016). Severity is assessed according to the depth of renal parenchymal damage and involvement of the urinary collecting system and ren...
Abnormal renal rotation (renal malrotation) refers to an anatomical variation in the position of the kidneys, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding.
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
central core comprised of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessels a...
Accessory renal arteries are a common variant and are present in ~25% (range 20-30%) of the population.
Sometimes, the term extrarenal artery may be used 2 with a further subclassification of:
aberrant renal artery: supplying the superior and/or inferior pole of the kidney
accessory renal art...
Acquired cystic kidney disease (ACKD) is a condition that occurs in patients with end-stage kidney disease (ESKD), especially when on dialysis treatment, and who do not have a history of other cystic renal disease.
Its incidence increases with the amount of time a patient is azot...
Acute idiopathic scrotal oedema (AISE) is a self-limiting condition characterised by marked oedema of the skin and dartos fascia without involvement of the deeper layers, testes, or epidydimis. It is an important condition to recognise in order to avoid unnecessary surgical exploration.
Acute pyelonephritis remains common and continues to have significant morbidity in certain groups of patients.
The incidence of acute pyelonephritis parallels that of lower urinary tract infections: approximately five times more common in females with a sharp increase following pu...
Adenocarcinoma of the bladder is rare, and accounts for only ~1% of all bladder cancers (90% are transitional cell carcinomas).
Metaplasia of urinary bladder induced by chronic irritation or infection can lead to adenocarcinoma. Pathological types of adenocarcinoma of urinary bladder...
Adenomatoid tumours of the scrotum are benign, solid extra testicular lesions that can originate from the epididymis, tunica vaginalis, or spermatic cord (90% derived from the funiculus).
They are the most common extra testicular neoplasm, and most common tumour of the epididymis,...
Adrenal adenomas are the most common adrenal mass lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adrenal metastases or other ad...
Adrenal calcification is not a rare finding in healthy asymptomatic people and is usually the result of previous haemorrhage, or tuberculosis. Addison's disease patients only occasionally have calcification.
sepsis: Waterhouse-Friderichsen syndrome
An adrenal collision tumour or collision tumour of the adrenal gland is an uncommon tumour of the adrenal gland, where two histologically distinct tumours abut each other or are in close proximity.
Collision tumours have been reported in nearly every organ, for example collision tumo...
Primary adrenal cortical carcinoma is a highly malignant but rare neoplasm. It may present as a hormonally active or inactive tumour.
Although men and women are affected equally, functioning tumours are more common in females, who are also more likely to have an associated endocr...
The adrenal (suprarenal) glands lie anteromedial to the kidneys. They are paired organs of the endocrine system but are quite asymmetric in shape.
Each gland is enclosed in the perirenal fascia and each have a body and two limbs - medial and lateral. However, the right adrenal g...
Adrenal gland trauma most commonly results from blunt force trauma.
Adrenal gland trauma is present on 1-2% of CT imaging in blunt trauma although the occurrence is thought to be much higher as injury has been demonstrated at 28% in one autopsy series 1-4.
The right adrenal glan...
Adrenal haemangiomas are rare benign tumours that are usually incidentally identified (one example of an adrenal incidentaloma). Its significance mainly relates to the difficulty in differentiation from other malignant lesions.
Although these can be found at any age, they are mos...
Adrenal haemorrhage can result from a variety of causes (traumatic as well as non-traumatic). When unilateral, it is often clinically silent. In contrast, bilateral adrenal haemorrhage can lead to catastrophic adrenal insufficiency.
The large majority of patients with uni...
Adrenal hyperplasia refers to nonmalignant growth (enlargement) of the adrenal glands and is a rare cause of ACTH-independent Cushing syndrome with unilateral adrenal cortical adenomas being the commonest. 20% of Conn syndrome cases are secondary to adrenal hyperplasia. In diffuse hyperplasia, ...
Adrenal lesions cover a broad spectrum from benign to neoplastic entities. Due to increased use of cross sectional imaging they are frequently detected as incidental lesions.
Radiology plays a significant role in differentiation. Cross sectional imaging is the mainstay of imaging for identifyin...
Adrenal metastases are the most common malignant lesions involving the adrenal gland. Metastases are usually bilateral but may also be unilateral. When unilateral involvement is thought to be more prevalent on the left side (ratio of 1.5:1).
They are thought to be present in up to...
Adrenal myelolipomas are rare benign, and usually asymptomatic, tumours of the adrenal gland characterised by the predominance of mature adipocytes.
On imaging, they usually present as large masses with a variable amount of fat-containing components.
Rare tumours with estimated ...
Adrenal pseudocysts account for approximately 39% of adrenal cysts, and are more likely than simple adrenal cysts to be symptomatic.
Pseudocysts do not have an epithelial lining and typically arise after an episode of adrenal haemorrhage.
Adrenal pseudocysts appear as a ...
Adrenal vein sampling (AVS) is a procedure used to confirm autonomous hormone production, if it is unilateral or bilateral, to guide further treatment.
AVS is commonly performed in primary aldosteronism, being indicated to identify aldosterone-secreting adenomas and to differentiate...
Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15 minutes delayed CT-scans. It is primarily used to diagnose adrenal adenoma.
[(HUportal venous phase) - (HUdelayed)] / [(HUportal venous phase) - (HUnon-enha...
Adrenocorticotropin independent macronodular adrenocortical hyperplasia (AIMAH) is considered a rare form of macronodular adrenal hyperplasia. It is an uncommon cause of primary adrenal hypercortisolism.
Patients with AIMAH tend to present 10 years on average than the tim...
Adult cystic renal disease comprises multiple distinct hereditary and non-hereditary disease processes.
adult polycystic kidney disease (APCKD), a.k.a. autosomal dominant polycystic kidney disease (ADPCKD)
medullary cystic kidney disease
von Hippel-Lindau di...
Aggressive angiomyxomas are rare pelvic tumours that arise in the pelvis and typically cross the the levator ani muscles. Despite its name, it is essentially a benign tumour and the term "aggressive" is given due to predilection for local recurrence. Only rarely does it metastasise.
Alport syndrome is an X-linked recessive disease characterised by:
sensory neural hearing loss: typically high frequency 2
anterior lenticonus: most common ocular abnormality; may result in cataracts
perimacular pigmentary changes
flecks around the fovea 2...
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge.
Head and neck anatomy
Abdominal and pelvic anatomy
Lower limb anatomy
Upper limb anato...
Androgen insensitivity syndrome (AIS), also known as the testicular feminisation syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings.
The incidence may vary dependent on whether it i...
Angiomyofibroblastoma like tumour of scrotum is a rare well-defined slow growing mesenchymal extratesticular nonepididymal tumour which rarely seen in perineum and scrotum of older male patients. A similar tumour can occur in the vulval region in females.
In males, they seen in m...
Antegrade ureteric stents are performed under fluoroscopic guidance, typically by an interventional radiologist or urologist. It is performed via percutaneous access from the kidney. It is usually performed using the access from a prior percutaneous nephrostomy, a so-called 2-step procedure, alt...
The anterior pararenal space is the portion of the retroperitoneum that lies between the posterior surface of the parietal peritoneum and the anterior reflection of the perirenal fascia.
It contains the duodenum, pancreas and retroperitoneal segments of the ascending and descendi...
Antopol-Goldman lesions are very rare presentations of subepithelial haemorrhage in the renal pelvis, presenting as discrete mass-like haematomas.
The cause of these lesions is uncertain, although non-steroidal anti-inflammatory drug (NSAID) overuse, trauma, and amyloidosis have been...
Artificial urinary sphincters replace the function of the natural urinary sphincter in patients with sphincter damage or neurologic disease, most commonly as a result surgery for prostate cancer.
They are sometimes used in combination with a bladder neck stent.
A typical design inc...
Asbestos related disease, in particular affecting the lung, comprise of a broad spectrum of entities related to the inhalational exposure to asbestos fibres. They can be divided into benign and malignant changes 1-3.
Benign pleural and parenchymal lung disease
asbestos related benign pleural d...
Atypical small acinar proliferations (ASAP) are premalignant lesions of the prostate, which can be found in as many as 5% of prostate biopsies. They are suspicious glands without adequate histologic atypia to establish a definitive diagnosis of prostate cancer. Some studies showed that there is ...
The aubergine sign (also known as egg-plant sign or deformity) is a clinical sign of a fractured penis. Haemorrhage beyond the tunica albuginea produces swelling and bruising of the penis simulating the appearance of an aubergine.
Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as "adult polycystic kidney disease", is as the name would suggest, a hereditary form of adult cystic renal disease.
Autosomal dominant polycystic kidney disease is one of the ...
Autosomal recessive polycystic kidney disease (ARPKD) is one of many paediatric cystic renal diseases.
On imaging, it usually presents on ultrasound with enlarged echogenic kidneys with multiple small cysts. Liver involvement with coarse echotexture, biliary tract cystic changes, and portal hyp...
The avascular plane of Brodel is the section of renal parenchyma in the posterior kidney that is relatively avascular. The reason for its relative avascularity is that it represents the plane where the renal artery branches meet.
It is located just posterior to the lateral convex border of the ...
Azoospermia refers to complete absence of sperm in the semen. It accounts for 5-10% of male infertility 1.
It can be obstructive or non-obstructive, e.g. primary testicular failure. This differentiation is of utmost importance, as obstructive azoospermia can be corrected by surgical ...
Balkan nephropathy refers to a degenerative interstitial nephropathy endemic to the Balkan states, which is associated with a very high rate of transitional cell carcinomas of the renal pelvis and upper ureter.
The condition is largely restricted to the villages along the Danube ...
In renal imaging, the balloon on a string sign refers to the appearance on IVU in ureteropelvic junction obstruction. It is seen due to the high and eccentric point of exit of ureter from a dilated renal pelvis.
Bardet-Biedl syndrome (BBS) previously known as the Laurence-Moon-Bardet-Biedl syndrome (LMBBS) is a rare autosomal recessive hereditary condition.
The clinical spectrum includes
retinal anomalies: similar to that of retinitis pigmentosa
Bartter syndrome is a rare inherited renal disorder.
Bartter syndrome is characterised by hyperplasia of the juxtaglomerular cells along with:
hypotension or normotension
elevated plasma renin
Batson venous plexus (Batson veins) is a network of veins with no valves that connect deep pelvic veins draining the bladder, prostate and rectum to the internal vertebral venous plexus 1. These veins are important because they are believed to provide a route for spread of pelvic cancer metastas...
The bear paw sign is seen in xanthogranulomatous pyelonephritis and refers to the cross-sectional appearance of the kidney which is said to resemble the paw of a bear. The renal pelvis is contracted whereas the calyces are dilated, mimicking the toe-pads of the paw.
Behçet disease is a multi-systemic and chronic inflammatory vasculitis of unknown aetiology.
The mean age at which Behçet disease occurs is 20-30 years. The disease is most prevalent in the Mediterranean region, Middle East and East Asia. The highest incidence has been reported in...
A bell clapper deformity is a predisposing factor in testicular torsion in which the tunica vaginalis joins high on the spermatic cord, leaving the testis free to rotate. Bell clapper deformity predisposes to intravaginal torsion of the testis.
Benign prostatic hyperplasia (BPH) is an extremely common condition in elderly men and is a major cause of bladder outflow obstruction.
The term benign prostatic hypertrophy was formerly used for this condition, but since there is actually an increase in the number of epithelial a...
A bifid ureter, or ureter fissus, is an example of incomplete duplication of a duplex collecting system.
Present in ~5% (range 1-10%) of the population 1-2.
A bifid ureter is formed when there is a duplex kidney (separate pelvicalyceal collecting systems) drain i...
The differential for bilaterally enlarged adrenal glands is relatively limited:
micronodular adrenal hyperplasia
macronodular adrenal hyperplasia
adrenocorticotropin (ACTH)-independent macronodular adrenocortical hyperplasia (AIMAH) 2
Bilateral renal enlargement can arise from a number of causes which include 1:
diabetic nephropathy (common)
renal involvement with lymphoma
adult dominant polycystic kidneys (ADPKD)
bilateral renal cell carcinoma
Bilateral testicular lesions have a relatively limited differential diagnosis.
lymphoblastic leukemia (acute or chronic)
primary testicular lymphoma is rare but the testes are often the site of lymphoma/leukemia recurrence due to the chemoptherapy inabil...
Bilobed testis, also known as incomplete unilateral polyorchidism, is a very rare variant in children.
The exact aetiology is unknown but is thought be a form of incomplete polyorchidism. It has been proposed that bilobed testis results from incomplete division of the urogenital ridg...
Birt-Hogg-Dubé (BHD) syndrome is a genetic multisystemic disease mainly characterised by:
multiple lung cysts and secondary spontaneous pneumothoraces
multiple bilateral renal tumours (particularly chromophobe renal cell cancer and oncocytoma)
cutaneous manifestations (angiofibromas, perifoll...
Bladder and ureteric tuberculosis (TB) refers to infection of ureters and urinary bladder with M. tuberculosis.
characteristic beaded appearance due to alternate areas of strictures and dilatation (chronic state)
acute: ureteral wall thickening
A simple mnemonic to recall the common causes of bladder calcification is:
C: cytotoxic: see radiation and chemotherapy induced cystitis
R: radiation: see radiation and chemotherapy induced cystitis
I: interstitial cystitis
Bladder calculi occur either from migrated renal calculi or urinary stasis. Bladder calculi can be divided into primary and secondary stones:
primary: stones form de novo in the bladder
secondary: stones are either from renal calculi which have migrated down into the bladder, or from concretio...
Bladder exstrophy (also known as ectopia vesicae) refers to a herniation of the urinary bladder through an anterior abdominal wall defect. The severity of these defects is widely variable.
The estimated incidence of bladder exstrophy is 1:10,000-50,000 live births 4,6. There is a ...
A bladder inflammatory pseudotumour is a nonneoplastic proliferation of cells.
This entity is more common in adults, with a mean age at diagnosis of 38 years.
Patients present most commonly with an ulcerating bleeding mass, hematuria, and voiding symptoms....
Bladder outlet obstruction (BOO) can come from a number of conditions affecting the urethra and/or bladder outlet.
Patients often present with difficulty in urination, retention and urinary discomfort 2.
Obstruction can be caused by multiple eitolgies b...
A mnemonic for the causes of bladder wall calcification is:
C: cystitis post radiation therapy / chemotherapy / chronic infection
E: eosinophilic cystitis
Differential diagnosis for bladder wall thickening depends on whether the bladder is adequately distended. The bladder wall may be thickened if:
>3 mm when distended
>5 mm when nondistended
If the bladder is not distended, then it is difficult to exclude artifactual thickening from a co...
A Boari bladder flap is one of the options for ureteric reimplantation when the diseased ureteric segment is long (e.g. more than 5 cm). It is useful in the management of lower ureteric strictures and can be performed as either an open or laparoscopic procedure. It involves tubularisation of a f...
The Bosniak classification system of renal cystic masses divides renal cystic masses into five categories based on imaging characteristics on contrast-enhanced CT. It is helpful in predicting a risk of malignancy and suggesting either follow up or treatment.
A bouquet of flowers appearance is a description given to the appearances of medullary sponge kidney on a traditional intravenous pyelogram (IVP) study. The ectatic distal collecting ducts contain the microcalcification typical of the disease. This is also known as a 'bunch of grapes' appearance...
Brachytherapy, also known as sealed source radiotherapy or endocurietherapy, is a form of radiotherapy where a radioactive source is placed, under the guidance of imaging, within or next to the area requiring treatment.
Brachytherapy is commonly used to treat localised prostate cancer, breast c...
Branchio-oto-renal (BOR) dysplasia is a rare syndromic disorder characterised by:
can involve the outer, middle, and inner ear associated with conductive, sensorineural, or mixed hearing impairment
branchial fistulae and branchial cleft cysts
Bullet and bodkin sign is the appearance of the ureter when there is an abrupt transition in the ureteral caliber. Bullet in the name is represented by the dilated proximal ureteric segment which appears to be perched on the constricted / non dilated encased ureter which gives an appearance of a...
A burned out testis tumour may be present if there is metastatic retroperitoneal lymphadenopathy, but the primary testicular tumor is a relatively occult, scarred intratesticular focus. Approximately 50% of the "burned out" tumors continue to harbor malignant cells.
Calciphylaxis, or calcific ureamic arteriolopathy, is a rare condition which manifests as subcutaneous vascular calcification and cutaneous necrosis (small blood vessels of the fat tissue and the skin). Some authors describe as a syndrome of vascular calcification, thrombosis and skin necrosis.
The calyceal crescent sign (Dunbar's crescents) refers to the early IVP appearance of markedly dilated renal calyces. It is formed by early contrast opacification of the dilated collecting ducts and ducts of Bellini with the characteristic shape as a result of the associated enlarged calyces.
Calyceal microlithiasis or more specifically renal calyceal microlithiasis is defined as <3 mm hyperechoic foci noted within the renal calyces on gray scale ultrasonography 1. It has been considered as a precursor for renal stone formation.
The patient may be asymptom...
Cannonball metastases refer to large, well circumscribed, round pulmonary metastases that appear, well, like cannonballs. The French term "envolée de ballons" which translates to "balloons release" is also used to describe this same appearance.
Metastases with such an appear...
Carcinogens are substances known to cause cancer. They include:
Nasopharynx / nasal passage
ionising radiation (not technically a substance)
polyaromatic hydrocarbons (PAH)
There are numerous causes of Urinary bladder diverticulae:
Primary (congenital or idiopathic)
Hutch diverticulum (in paraureteral region)
Bladder outlet obstruction
bladder neck stenosis
posterior urethral valve
prostatic enlargement (hypertrophy; carcinoma)...
Staging of cervical cancer can either be based on the TNM or FIGO system.
Revised FIGO staging of cervical carcinoma 2009 8
stage 0: cervical intraepithelial neoplasia (HSIL or CIN III)
stage I: confined to cervix
stage Ia: invasive carcinoma only diagnosed by microscopy.
Ia1: stromal inva...
Cervical intraepithelial neoplasia (CIN) (also known as cervical dysplasia) is the potentailly premalignant stage in the dysplastic changes in the squamous epithelium of the cervix.
Grading of CIN is based on the degree of dysplasia seen in a sample of cervical tissue:
similar to condy...
Cesarean section scar diverticulums are a defect in the lower uterine cavity at the site of the cesarean section scar.
in a study was found to be the only finding in patients with bleeding disturbances
There are many signs in radiology that are related to Christmas:
snowcap sign in avascular necrosis
in total anomalous pulmonary venous return
in pituitary macroadenomas
snowstorm appearance in complete hydatidiform and testicular microlithiasis
holly leaf sign in calcified pl...
Chromaffin cells are neuroendocrine cells found predominantly in the medulla of the adrenal gland. They are also found in other ganglia of the sympathetic nervous system and are derived from the embryonic neural crest.
They arise in the fifth week of fetal development when neuroblas...
Chronic kidney disease (CKD), also known as chronic renal failure, is a progressive loss of glomerular function caused by a long-standing renal parenchymal disease. It is present when the glomerular filtration rate (GFR) is less than 60 ml/min/1.73 m2 for three consecutive months or greater than...
Chronic periaortitis is an inflammatory condition which typically involves the infrarenal portion of the abdominal aorta. It is a rare disease usually occuring in middle-aged men.
It has various clinical presentations:
idiopathic retroperitoneal fibrosis (IRF)
perianeurysmal retroperitoneal f...
Chronic primary adrenal insufficiency has a number of causes. Primary adrenal insufficiency is termed Addison disease.
idiopathic atrophy: autoimmune disease
tuberculosis: 25% calcify
Chronic pyelonephritis is form of pyelonephritis where there are longstanding sequelae of renal infection. At the time of writing there is still no definitive consensus at to whether the condition represents an active chronic infection, arises from multiple recurrent infections, or represents st...
Circumaortic left renal vein, also known as circumaortic renal collar is an anomaly of left renal vein when a supernumerary or accessory left renal vein passes posterior to the aorta, apart from the normal renal vein passing anterior to the aorta. This anomaly is potentially hazardous, if unreco...
A circumcaval ureter, or retrocaval ureter, is a developmental anomaly of the inferior vena cava (IVC). Unfortunately both terms suggest that the ureter is at fault, whereas in reality it is the IVC. They are of two types:
Many patients with this anom...
Citrate is a compound examined in MR spectroscopy in the setting of possible prostate carcinoma. Citrate resonates at 2.6 ppm and is decreased in prostate cancer.
For more information go to: MR spectroscopy in prostate cancer
The claw sign is useful in determining whether a mass arises from a solid structure or is located adjacent to it and distorts the outline.
It refers to the sharp angles on either side of the mass, which the surrounding normal parenchyma forms when the mass has arisen from the parenchyma. As su...
Clear cell sarcoma (CCS) of the kidney are a rare mesenchymal tumour that account for ~5% of primary renal neoplasms in paediatric population 1.
CCS is the second most common primary malignant renal neoplasm after Wilms tumour, with an annual incidence of 20 cases in the United S...