Prostatic sarcoma is an uncommon and heterogenous group of tumor arising from mesenchymal cells in and around the prostate.
In children the most common tumor type is a prostatic rhabdomyosarcoma, which accounts for approximately a third of all prostatic sarcomas 1.
In adults leiom...
Prostate specific antigen (PSA) is currently used as a tumor marker for prostate adenocarcinoma.
PSA is a 33 kilodalton glycoprotein produced in prostate epithelial cells. Its normal physiologic role is as a liquefying agent for seminal fluid; only a tiny amount leaks into the blood, therefore ...
Prostate-specific membrane antigen (PSMA) (also known as glutamate carboxypeptidase II) is a type II transmembrane glycoprotein that has become an increasingly prominent imaging biomarker 1. PSMA has emerged as a useful target in PET imaging of prostate cancer, especially in the evaluation of sm...
Prostatic abscesses can be a rare complication of prostatitis.
Prostatic abscesses have become relatively uncommon due to the increased use of antibiotic therapy in those with prostatitis. It tends to affect diabetic and immunosuppressed patients. Most patients affected are aroun...
Prostatic artery embolization (PAE) is a minimally invasive procedure option utilized to treat the benign prostatic hyperplasia (BPH).
PAE has been used for controlling prostatic hemorrhage (such as those associated prostate cancer) since 1970. However, its use in the treatment of...
Prostatic calcification is a common finding in the prostate gland, especially after the age of 50. They may be solitary but usually occur in clusters 7.
They are rare in children, infrequent below 40, and common in those over 50. Their number and size increase with age 8.
Prostatic carcinoma ranks as the most common malignant tumor in men and the second most common cause of cancer-related deaths in men. Prostatic adenocarcinoma is by far the most common histological type and is the primary focus of this article.
It is primarily a disease of the eld...
Prostatic cystadenoma or multilocular cystadenoma of prostate is a rare benign neoplasm arising in the prostate gland.
If lesions are considerably large they may also be termed giant multilocular cystadenomas of the prostate.
Lesions are histologically characterized by glands and cy...
Prostatic infarction refers to necrosis of the prostate gland tissue from a lack of blood supply.
Histology slices on biopsy specimens may show reactive atypia 3.
prostatic artery embolization
presumed pelvic ischemia after
cross-clamping of the aorta for corona...
Prostatic tuberculosis or tuberculous prostatitis is an uncommon extrapulmonary manifestation of Mycobacterium tuberculosis infection.
Primary tuberculosis of the prostate is rare. Genitourinary tuberculosis contributes to 5-10% of extrapulmonary cases of tuberculosis in developed...
Prostatic utricle refers to Mullerian duct remnant in males which often manifests as a sac having a slit like orifice at the apex of verumontanum. This projects upward and backward into the substance of the prostate gland.
prostatic utricle cyst
Prostatic utricle cyst (or utricular cyst) (PUC) is an area of focal dilatation that occurs within the prostatic utricle.
They are midline cystic masses in the male pelvis and can be very difficult or impossible to distinguish from a Mullerian duct cyst.
Utricle cysts are most of...
The prostatic venous plexus is a network of veins around the anterolateral aspect of the prostate and anterior to the bladder. Tributaries include:
deep dorsal vein of the penis
anterior vesical rami
The receipt of blood from the vesical and prostatic rami connect the prostati...
Prostatitis refers to an infection or inflammation of the prostate gland that presents as several syndromes with varying clinical features. Prostatitis is a clinical diagnosis and imaging is useful to evaluate abscess formation.
The National Institutes of Health (NIH) have classifie...
Prostatomegaly is a term used to generally describe enlargement of the prostate gland from whatever cause. Usually, the prostate is considered enlarged on imaging when it measures beyond 30 cc (30 grams) in size.
The term prostatomegaly is often used interchangeably with benign pr...
Prune belly syndrome, also known as Eagle Barrett syndrome 3 or triad syndrome, is a rare anomaly comprising a specific constellation of features. It consists of three major findings:
gross pelvi-calyceal and ureteric dilatation with renal dysplasia 7
anterior abdominal wall underdevelopment (...
The PSA density (PSAD), is a calculation performed at diagnosis and is the serum PSA level (ng/mL) divided by the volume of the prostate gland (mL)1. Prostate volume is calculated from TRUS measurements2,3.
Alternatively, PSAD may be calculated using MRI measurements3 of prostate volumes or le...
Pseudobladder refers to a pelvic cystic mass that simulates the urinary bladder.
The location of the lesion should allow differentiation from the bladder but if doubt exists and clinical necessity arises, a delayed phase CT or MRI with excreted contrast or IDC-administered retrograde contrast f...
Pseudoenhancement is an artifact encountered with contrast-enhanced CT, whereby the calculated density of a lesion is inaccurately increased. This phenomenon is most often problematic during evaluation of renal cysts by CT.
On CT, it can be challenging to distinguish cystic versus solid renal l...
Pseudohydronephrosis (plural: pseudohydronephroses) refers to normal anatomy or non-significant pathologies that may mimic hydronephrosis. There is usually fluid-density material within a dilated part of the urinary tract, but without other signs of obstruction such as retroperitoneal fat strand...
Pseudoureterocoeles are acquired dilatations of the submucosal portion of the distal ureter that mimic simple ureteroceles. The appearance of the radiolucent wall surrounding the dilated distal ureteral segment (cobra head sign) is an important differentiating point.
The distinction is importa...
A psoas hitch is a method of ureteric re-implantation following distal ureteric resection or injury.
The reconstruction is indicated when the distal ureter is injured or resected for cancer or stricture disease, and the remaining portion of ureter cannot reach the bladder for a ureteroneocystot...
Pulmonary-renal syndromes refer to a group of conditions that can affect the lung and kidneys. These conditions are typically characterized by diffuse alveolar hemorrhage and glomerulonephritis.
Diseases that can result in a pulmonary-renal syndrome includes:
certain pulmonary vasculitides
A putty kidney refers to a pattern of renal calcification associated with renal tuberculosis conventionally described on plain radiography. The calcification is characteristically very homogeneous and ground glass-like, representing calcified caseous tissue 3,4. Premkumar et al. labeled calcific...
Pyelography (or "pyelogram") refers to imaging of the urinary collecting system.
The term is most often encountered in 'intravenous pyelography' (or "IVP"). For some, this is a misnomer and a test that images intravenous contrast as it travels through the kidney parenchyma into the urinary coll...
Pyelonephritis (plural: pyelonephritides) refers to an upper urinary (renal) tract infection with associated renal pelvis, renal calyceal and renal parenchymal inflammation, and comprises a heterogeneous group of conditions.
Pyelostomy is a rarely performed procedure in which an externalized catheter drains the renal pelvis. It is different from a nephrostomy in that the catheter in a pyelostomy enters the renal pelvis directly without passing though the renal parenchyma. It is much more prone to complication than a...
Pyonephrosis is a term given to an infection of the kidney with pus in the upper collecting system which can progress to obstruction.
Pyonephrosis may be suspected when the clinical symptoms of fever and flank pain are combined with the radiologic evidence of urinary tract obstruction 1. Debris...
Both radiation and chemotherapy can result in severe hemorrhagic cystitis, the appearances of which vary with time from the therapy. It can be divided into acute and chronic.
In the acute phase of radiation and chemotherapy cystitis, there is hemorrhagic cystitis secondary to denudation...
Randall's plaques are described as subepithelial calcification of the renal papilla 1 which are <2 mm in their greatest dimension. They act as an anchor for calcium oxalate crystals and are considered to be a predisposing factor for renal stone formation.
RASopathies are a class of developmental disorders caused by germline mutations in genes that encode for components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway.
As a group, RASopathies represent one of the most common malformation syndromes, with an in...
Radiological manifestations of recreational drug use are not infrequently seen as the use of recreational drugs is widespread.
Interestingly, recent reports have suggested a decreasing incidence of reported drug use in the general population over the past decade, but it remains th...
The rectouterine pouch, also known as the rectovaginal pouch, cul-de-sac or pouch of Douglas, is an extension of peritoneum between the posterior wall of uterus and the rectum in females. It is the most dependent part of the peritoneal cavity and is analogous to the rectovesical pouch in males.
Rectovesical pouch is the forward reflection of the peritoneum from the lower third of the rectum to the upper part of the bladder in males.
The rectovesical pouch is the lowest part of the peritoneal cavity and usually contains loops of small bowel or sigmoid colon. It is 7.5 cm...
Renal abscess, like any other abscess, is a collection of infective fluid in the kidney. It is usually a sequela of acute pyelonephritis, where severe vasospasm and inflammation may occasionally result in liquefactive necrosis and abscess formation.
It can affect all ages and has ...
A renal adenoma is type of benign renal neoplasm.
It is traditionally classified into three distinct types 1
renal papillary adenoma
renal tubular adenoma
alveolar renal adenoma
Renal agenesis refers to a congenital absence of one or both kidneys. If bilateral (traditionally known as the classic Potter syndrome) the condition is fatal, whereas if unilateral, patients can have a normal life expectancy.
Unilateral renal agenesis affects approximately 1 in ...
Renal amyloidosis is rare as an isolated entity but can be associated with systemic amyloidosis.
Renal involvement is estimated to affect a large proportion of the patients with systemic amyloidosis, with about half of them dying of renal failure complications 8.
Renal angiomyolipomas (AML) are a type of benign renal neoplasm encountered both sporadically and as part of a phakomatosis, most commonly tuberous sclerosis. They are considered one of a number of tumors with perivascular epitheloid cellular differentiation (PEComas) and are composed of vascula...
Renal antibiomas are postinflammatory cystic fluid
collections during or after antibiotic treatment for acute
pyelonephritis. These are usually < 3 cm sized, with no or minimal
post contrast wall enhancement or thickening.
They may mimic a renal abscess or perinephric abscess.
Renal arterial cut-off sign, as the name suggests, is an abrupt termination of the contrast-opacified lumen of the renal artery. It may or may not be associated with contrast extravasation.
It is seen in a vascular injury, e.g. segmental or main renal artery thrombosis or occlusion.
The renal arterial resistive index (RI) is a sonographic index of intrarenal arteries defined as (peak systolic velocity - end diastolic velocity ) / peak systolic velocity. The normal range is 0.50-0.70. Elevated values are associated with poorer prognosis in various renal disorders and renal t...
Renal arteriovenous fistulae (AVFs) are anomalous direct communications between arteries and veins in the kidney, which may be confused with a renal arteriovenous malformation (rAVM).
The incidence of renal AVF is variable, estimated at 0.3-19% in native kidneys and 6-8% in re...
Renal arteriovenous malformations (renal AVMs) are an uncommon vascular anomaly, which may be confused with a renal arteriovenous fistula (renal AVF).
Like arteriovenous malformations elsewhere in the body, a renal AVM is formed by a connection between the arterial and venous structu...
The renal arteries originate from the abdominal aorta and enter the renal hila to supply the kidneys. Any variant in arterial supply is important to clinicians undertaking surgery or other interventional renal procedures.
They arise from the abdominal aorta at the L1-2 ...
Renal artery aneurysms (RAA) are considered the second most common visceral aneurysm (15-22%), most common being splenic artery aneurysm (60%). They are more common in females. Most of the lesions are saccular and tend to occur at the bifurcation of main renal artery.
RAAs occur i...
Renal artery dissection may occur as a result of the following processes 1:
aortic dissection extending to involve the renal artery
iatrogenic (e.g. catheterization)
connective tissue disease (eg. Marfan syndrome)
Renal artery occlusion can happen acutely due to in-situ thrombus, embolism, or dissection. Unless immediately treated, it can lead to renal infarction 1.
The condition is more common in the elderly, however, it may be seen in a younger age group if they have risk factors (describ...
Renal artery pseudoaneurysms are uncommon vascular finding, with the majority occuring after a renal intervention.
A renal artery pseudoaneurysm differs from a renal artery true aneurysm (as might occur in fibromuscular dysplasia) in that it does not involve all three layers of the a...
Renal artery stenosis (RAS) refers to a narrowing of a renal artery. When the process occurs slowly, it leads to secondary hypertension. Acute renal artery stenosis does not lead to hypersecretion of renin.
When the stenosis occurs slowly, collateral vessels form and supply the kidne...
Renal cell carcinomas (RCC) (historically also known as hypernephroma or Grawitz tumor) are primary malignant adenocarcinomas derived from the renal tubular epithelium and are the most common malignant renal tumor. They usually occur in 50-70-year old patients and macroscopic hematuria occurs in...
Renal cell carcinoma staging using the TNM staging system for renal cell carcinoma. Older but still widely used system in some practices is the Robson staging system.
TNM staging (7th edition)
T1a: tumor confined to kidney, <4 cm
T1b: tumor confined to kidney, >4 cm but <7 cm
Renal colic (also known as ureteric colic) refers to a pattern of abdominal pain most commonly caused by ureteric calculi. The pain (usually unilateral) is felt in the loin radiating down to the groin and is typically colicky (i.e. coming in waves) corresponding to peristalsis or spasm of the ur...
Renal coloboma syndrome (also known as papillorenal syndrome) is a rare condition that primarily affects kidney and eye development.
Affected individuals typically have hypoplastic kidneys, which can lead to end-stage renal disease. Approximately 10% of children with hypodysplastic kidneys have...
Renal cortical defects have a variety of causes, and present on imaging as an area of focal cortical thinning or absence of renal cortex, sometimes accompanied by focal caliectasis.
The differential diagnosis for a renal cortical defect includes 1,2:
Renal cortical necrosis occurs as a result of severe systemic illness in a variety of settings and can result in permanent renal impairment.
severe hemodynamic shock
traumatic blood loss
Renal cyst is a generic term commonly used in description of any predominantly cystic renal lesion. The majority of parenchymal cystic lesions represent benign epithelial cysts; however, malignancy such as renal cell carcinoma may also present as a cystic lesion 8.
Renal cysts are usually evalu...
Renal cysts and diabetes syndrome (RCAD), also known as maturity-onset diabetes of the young, type 5 (MODY5), refers to the combination of renal cortical cysts and diabetes mellitus in patients with mutations in the HNF1B gene. When renal cysts are associated with these mutations without disturb...
Renal dysgenesis is a very broad term which can include any form underdevelopment of the kidneys. The spectrum includes:
renal agenesis: complete lack of formation
renal hypoplasia: partial lack of formation
Some authors also classify any form of renal maldevelopment affecting size, shape of ...
Renal epithelial cysts, also known as simple renal cysts, are common benign lesions of the renal parenchyma. Since they are uncommon in children and progressively more common with age, they are considered acquired lesions.
overall high prevalence
increasingly common with age 1,2
Renal forniceal or calyceal rupture is the radiographic finding of a perirenal urine leak as a result of ureteric obstruction.
The renal fornices are the thin pointed projections, arising from the lateral aspects of each minor calyx, and extending a short distance into the renal column...
Renal hemosiderosis results from accumulation of hemosiderin in the kidneys. It is usually considered a benign and incidental radiologic finding and rarely results in clinically apparent renal dysfunction.
Renal hemosiderosis is a known complication of the following conditions:
A renal hilar lip is a developmental anomaly of the kidney. It is an infolding of the cortex at the level of the renal sinus and in this region the renal cortex appears thicker.
On imaging it appears as supra- or infra-hilar cortical bulges. At certain levels of cross-se...
Renal hydatid infection is extremely rare manifestation of hydatid disease.
For a general discussion, and for links to other system specific manifestations, please refer to the article on hydatid disease.
Renal hydatid infection is seen in less than 5% of patients with hydatid d...
Renal hypoplasia refers to a congenitally small kidney where there is essentially normal residual parenchyma but smaller calyces, lobules and papillae. This is in contrast to renal atrophy where renal development was initially normal but the kidney has become smaller secondary to various other p...
Renal infarction results from interruption of the normal blood supply to part of, or to the whole kidney. The main imaging differential diagnosis includes pyelonephritis and renal tumors.
The demographics of affected patients will depend on the underlying cause, although as most c...
Renal intraparenchymal acceleration time is a parameter used in assessing renal arterial stenosis on Doppler ultrasound. It is the time taken from the start of systole to peak systole.
normal range: a value of usually < 0.07 seconds is taken as being within normal limits 1.
Renal lymphangiomas, also known as renal lymphangiectasia, are a rare disorder, where there is dilatation of perirenal, perapelvic, and intrarenal lymphatics. The diagnosis can be suggested by imaging, and aspiration of chylous fluid is usually confirmatory.
For a broader discussion, please re...
Renal lymphoma is usually a part component of multi-systemic lymphoma - primary renal lymphoma is unusual.
Typical imaging findings are multiple bilateral hypodense or infiltrative renal masses.
While renal lymphoma has an autopsy incidence of ~45% (range 30-60%) in lymphoma pati...
A renal mass can be broadly divided into two broad categories:
Renal medullary carcinoma is a rare and highly aggressive variant of renal cell cancer centered in the renal medulla.
Renal medullary carcinoma occurs almost exclusively in adolescent and young adult blacks with sickle cell trait or hemoglobin SC disease but not with homozygous h...
Renal milk of calcium cysts refer to the appearance of a calcium precipitate found either within a calyceal diverticulum, that has lost communication with the collecting system, or within a simple renal cyst.
Renal milk of calcium cysts are typically asymptomatic.
The RENAL nephrometry scoring system was developed to categorize renal masses into low, intermediate and high complexity, based on cross-sectional imaging findings. Its purpose is to aid in decision making, patient counseling, surgical planning, and patient follow-up, as well as academic reporti...
Renal oncocytomas are relatively benign renal tumors. The main clinical importance of this lesion is the difficulty in pre-operatively distinguishing it from renal cell carcinomas, as epidemiology, presentation, imaging and even histology can be very similar.
Renal oncocytomas ac...
Renal oncocytosis, also known as renal oncocytomatosis, is the presence of many concurrent renal oncocytomas with or without renal cell carcinomas. Typically a dominant larger tumor is present, with bilateral innumerable smaller tumors. Sometimes renal failure may develop 1.
Renal osteodystrophy (ROD), also known as uremic osteopathy, is the constellation of musculoskeletal abnormalities that occur in patients with chronic renal failure, due to concurrent and superimposed:
osteomalacia (adults)/rickets (children)
secondary hyperparathyroidism: abnormal calcium and...
Papillary adenomas of the kidney are benign renal neoplasms arising from the renal tubular epithelium and almost always located within the cortex. They fall under the general category of renal adenomas, and are considered one of the commonest of renal epithelial neoplasms.
Renal papillary necrosis refers to ischemic necrosis of the renal papillae. Necrosis also occurs in the medullary pyramids.
Patients can present with both acute episodes or chronic renal papillary necrosis. Calyceal or ureteral obstruction by sloughed papillae manifest with f...
Mnemonics for the causes of renal papillary necrosis are plentiful and include:
AD SPORT C: a list of causes in decreasing order of incidence
Most common causes:
N: non-steroidal anti-inflammatory drugs (NSAIDs)
S: sickle cell disease
The renal pelvis (or, more rarely, the renal infundibulum) forms part of the pelvicalyceal system of the kidney and is the connection between the calyces and the ureter.
The renal pelvis is triangular in shape, lies posteriorly in the renal hilum surrounded by fat and vessels and...
A renal pseudotumor is a mass that will simulate a tumor on imaging but is composed of non-neoplastic tissue. There are many examples 1:
prominent column of Bertin
persistent fetal lobulation
cross-fused renal ectopia
renal hilar lip
Renal replacement lipomatosis is a rare condition characterized by fatty tissue proliferation in the renal sinus and perinephric space with marked destruction/atrophy of renal parenchyma (due to chronic inflammation).
Patients usually present with non-specific complaints ...
Renal replacement therapy (RRT) (also called renal dialysis or just dialysis) is used to supplement renal function in patients with either end-stage chronic kidney disease or medically-refractory acute renal impairment.
Haemodialysis refers to the diffusion of solutes in solution across...
The renal sinus is a fat-filled compartment of the kidney.
The renal sinus is a fatty compartment located within the medial aspect of the kidney. It communicates with the perinephric space. It contains the renal hilum and is bordered by renal parenchyma laterally.
Renal sinus cysts are simple renal cysts that lie within the renal sinus.
It is worth noting that some authors 5,6 use the term renal lymphangiectasia interchangeably. It is likely that true renal lymphangiectasia is a separate and rare disorder, and is thus discussed separately.
Renal sinus lipomatosis refers to a condition where there is excessive renal sinus fat replacement.
It results from renal parenchymal atrophy, inflammation, calculous disease, aging, or exogenous or endogenous steroids.
There is usually no or rarely little mass effect on the collect...
Renal sympathetic denervation (RSDN), also known as renal denervation, is an interventional procedure that uses radiofrequency ablation to destroy the nerve endings in the wall of the renal arteries. Endovascular (trans-catheter) techniques are an alternative to surgical sympathectomy.
This is a basic article for medical students and other non-radiologists
Renal tract calculi, also known as urolithiasis, refer to renal stone formation at any point along the renal tract (from kidneys to bladder and urethra).
This is a summary article; read more in our artic...
Renal transplantation is one, if not the most, common transplant procedures undertaken worldwide. Consequently, purposeful and incidental imaging of renal transplants and renal transplant-related complications are increasingly common. These include acute renal transplant rejection and chronic re...
Renal transplant rejection is one of the feared complications of renal transplantation.
In terms of onset, this can be broadly divided into two groups
acute renal transplant rejection
chronic renal transplant rejection: usually after one year post transplantation (at least after 3 months)
The recipients of renal transplants are susceptible to a number of complications. Incidence of each is variable and partially subject to specific surgical transplantation techniques and management patterns 3.
Renal transplant complications
These can be broadly categorized as perire...
The central approach of renal transplant ultrasound is to evaluate for possibly treatable surgical or medical complications arising in the transplanted kidney.
Institutions vary in the exact schedule of renal transplant ultrasound assessment, but it is common to obtain an initial ultrasound 24-...
Renal trauma can result from direct, blunt, penetrating and iatrogenic injury.
Renal injuries account for ~10% of abdominal trauma, and thus the demographic of affected individuals reflects that population. The incidence of renal injuries increases in pre-existing congenital or ac...