The characteristic shape of the crescent has been given to many radiological signs over the years.
crescent sign (disambiguation)
crescent sign (arterial dissection)
crescent sign (inguinal hernia)
crescent sign (intravenous pyelogram)
crescent sign (lung hydatid)
crescent sign (osteonecro...
The doughnut sign, also known as the bull's-eye, halo or ring sign, is the name of a distinctive appearance of a missed testicular torsion on scrotal scintigraphy.
In a missed torsion (i.e. established testicular infarction), there is a reactive hyperperfusion of the ipsilateral dartos muscle ...
Hypovascular retroperitoneal lesions are those which do not enhance in the late arterial and portal venous phases on CT. Some of these lesions may show progressive enhancement in the delayed phase due to their fibrous or myxoid matrix components.
Hypervascular retroperitoneal lesions are findings that enhance avidly in the late arterial phase with or without washout in the portal venous and delayed phases, on contrast-enhanced CT or MRI.
Early enhancement with slow washout
retroperitoneal paragangliomas - of...
The salt and pepper sign has been given to the heterogeneous echotexture of the enlarged kidneys on ultrasound in children with autosomal recessive polycystic kidney disease (ARPCKD).
Penile calcifications are a relatively rare finding. The commonest cause is Peyronie disease.
penile calciphylaxis (considered by some to be a form of calcinosis cutis)
penile urethral calculus
calcinosis cutis of the penis
idiopathic calcinosis cutis o...
Dent disease is a very rare inherited renal disorder that is characterized by proximal tubule dysfunction.
hypercalciuria, renal stones and nephrocalcinosis
proteinuria, although not presenting with nephrotic syndrome
The renal mass CT protocol is a multi-phasic contrast-enhanced examination for the assessment of renal masses. It is most often comprised of a non-contrast, nephrogenic phase and excretory phase. However, this article will cover the optional, corticomedullary phase too.
NB: This article is inte...
The excretory phase also known as the urographic phase is a postcontrast injection time range in which there is an optimal enhancement of the renal collecting systems.
The acquisition time depends on the intravenous device (central or peripheral), the concentration of the contrast me...
A commissure is a location at which two anatomical structures are united. Though the term most commonly refers to the commissures in the brain, there are a number which exist in the human body:
central nervous system
Pelvic organ prolapse refers to a pathological downward herniation of various pelvic organ structures into or through the perineum. It usually results from a pelvic floor weakness by impairment of various ligaments, fasciae, and muscles that support the pelvic organs.
The prolapse can include o...
Clear cell papillary renal cell carcinoma is a subtype renal cell carcinoma.
Generally uncommon but thought to be the fourth most common histologic type of renal cell carcinoma at the time of new classification (c. 2016) 1.
This subtype is characterized by low-grade, c...
The deep artery of the penis (male) or clitoris (female) is one of the two terminal branches of the internal pudendal artery. In males it can also be called the cavernosal artery.
Deep artery of the penis
Origin: the internal pudendal artery bifurcates terminally into the deep artery of the pe...
The dorsal artery of the penis (male) or clitoris (female) is one of the two terminal branches of the internal pudendal artery.
Dorsal artery of the penis
Origin: at its end the internal pudendal artery bifurcates into the deep artery of the penis and the dorsal artery of the penis at the ant...
The artery to the bulb of the penis (male) or vestibule (female) is a branch of the internal pudendal artery. It differs slightly in males and females.
Artery to the bulb of the penis
Origin: internal pudendal artery, distal to the perineal artery1.
a common penile artery, serving as the or...
Lymphangiomatosis is a rare mesenchymal disorder that is characterized by developmental "malformation" of multiple lymphatic channels (usually with dilatation).
If lymphatic channels are purely dilated and not malformed the term lymphangiectasia is usually used. If lymphangiomatosi...
The Mitrofanoff procedure, also known as appendicovesicostomy, is a surgical procedure where a conduit is created using the appendix to form a connection between the urinary bladder and skin surface. Intermittent catheterization is performed through the surgically constructed conduit, thus provi...
The perineal artery arises from the internal pudendal artery and supplies some of the perineal musculature and external genitalia.
Origin: branches off the internal pudendal artery, arising at the level of the posterior angle of the perineal membrane
Branches: it has two branches:
Carcinoma of the Littré glands is rare. The Littré (urethral) glands of the penis may be the origin of cancers of the penis, usually adenocarcinomas 1.
There are only a few scattered case reports of true Littré gland malignancy, although it is probably under-reported due to the fa...
A sphincter (TA: musculus sphincter) is a term used in anatomy to refer a ring of muscle which narrows a tube or closes off a bodily orifice 1.
external anal sphincter
internal anal sphincter
lower esophageal sphincter
Renal artery calcifications, also known as renovascular calcifications, are deposits of calcium salts on the wall of a renal artery, found incidentally on imaging, usually CT 1. They are associated with extrarenal atherosclerosis and linked to hypertension 2.
The term “renal artery...
A mnemonic to remember the commonest microorganisms responsible for urinary tract infections (UTIs) is:
K: Klebsiella spp.
E: Enterococcus faecalis / Enterobacter cloacae
E: Escherichia coli
P: Pseudomonas aeruginosa / Proteus mirabilis
S: Staphylococcus saprophyticus / Se...
A mnemonic to remember the basic indications of dialysis is
H: hyperkalemia (refractory)
A: acidosis (refractory)
V: volume overload
E: elevated BUN > 35 mM
E: edema (pulmonary)
A mnemonic to remember the commonest causes of hematuria is:
I PEE RBCS
P: pseudohaematuria (menses, dark urine)
E: external trauma
R: renal glomerular disease
B: benign prostatic hypertrophy
The nephrogenic phase, also known as the nephrographic phase or the renal parenchymal phase, is a postcontrast injection time range in which there is an optimal enhancement of the renal parenchyma including the medulla.
The acquisition time depends on the intravenous device (central ...
A tension hydrocele is a rare form of hydrocele that may result in impeded arterial inflow and venous outflow to and from the testis 1; testicular ischemia may result, leading to necrosis of the testicular parenchyma 2.
Tension hydrocele can be diagnosed through a combination of clin...
Squamous cell carcinoma (SCC) of the penis is an uncommon condition that often presents at an advanced stage. Imaging is more often used for staging than for the initial diagnosis. It is the commonest histological subtype of penile cancer.
Penile cancer is a relatively infrequent ...
Renal imaging in nuclear medicine is a method to assess the kidneys and collecting systems via multiple different radioactive tracers.Dynamic renal imaging is performed using Tc-99m MAG3 or Tc99m DTPA, and static renal imaging is performed with Tc-99m DMSA. In addition, Tc-99m DTPA can be used t...
The coiled catheter sign is sometimes seen in transitional cell carcinoma of the ureter. When a retrograde ureteropyelogram is attempted in the afflicted ureter, the catheter tip is seen to coil in the dilated portion of the ureter distal to the obstruction 1.
The CT chest-abdomen-pelvis protocol serves as an outline for an examination of the trunk covering the chest, abdomen and pelvis. It is one of the most common CT examinations conducted in routine and emergencies. It can be combined with a CT angiogram.
Note: This article aims to frame a genera...
A spontaneous rupture of the urinary bladder is usually on a background of a pre-existing pathology and is a urological emergency.
For a general discussion of the perforation of the urinary bladder, please refer to the article on urinary bladder rupture.
Intraperitoneal bladder t...
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...
Prostatic atrophy is characterized by reduced cytoplasm prostatic acinar cells and constitutes a benign mimic of prostate cancer not only on imaging but also histologically.
The term 'proliferative inflammatory atrophy (PIA)' is used if it is associated with inflammation.
The tulip sign is a sonographic clue for in-utero diagnosis of severe hypospadias.
The configuration of a tulip is given by the severe curvature of the penis in association with the penoscrotal transposition of a bifid scrotum.
History and etymology
The tulip sign was first described in 2002 ...
Prostatic leiomyomas are benign mesenchymal tumors of the prostate.
Prostatic leiomyomas are very rare 1-3.
Prostatic leiomyomas can present with voiding difficulties or obstructive symptoms 1.
Complications of prostatic leiomyomas include a...
Seminal vesicle cystadenomas are a benign subgroup of mixed epithelial and stromal tumors of the seminal vesicles.
Benign tumors of the seminal vesicles are very rare and so are cystadenomas 1.
Voiding difficulties or hematuria have been reported as clinica...
Seminal vesicle stones or calculi refer to solid mineralized pieces of material within the seminal vesicles.
Seminal vesicle calculi are rare and have been mainly reported after the age of 40 years 1.
Seminal vesicle calculi are often associated with hematospermia.
Seminal vesicle amyloidosis refers to the deposition of amyloid in the seminal vesicles and can occur as organ-limited amyloidosis and/or as part of systemic amyloidosis.
Amyloid deposition in the seminal vesicles is apparently commonly seen in elderly men with a prevalence rangin...
Prostatic acid phosphatase (PAP) also known as prostatic specific acid phosphatase (PSAP) is an enzyme generated by prostatic glandular tissue.
It can be used in immunohistochemistry to identify prostatic tissue including prostatic epithelium and prostatic ducts and is usually expressed ...
Mucinous adenocarcinomas of the prostate or colloid adenocarcinomas of the prostate are a variant of acinar adenocarcinoma and characterized by mucinous features.
Mucinous adenocarcinomas of the prostate are rare and account for less than 0.5% of prostate cancers 1-4.
Adenocarcinomas of the seminal vesicles are the most common malignant primary neoplasm of the seminal vesicles.
Primary adenocarcinoma of the seminal vesicles are very rare 1,2 and can be observed at a wide age range 2.
There is a lack of specific symptoms ...
Basal cell carcinoma of the prostate or prostatic adenoid basal proliferation of uncertain significance is a type of prostate cancer resembling adenoid cystic carcinoma of the salivary glands.
Other terms include 'adenoid cystic carcinoma', 'adenoid basal cell tumor', 'adenoid cyst...
Squamous neoplasms of the prostate include squamous cell carcinomas and adenosquamous carcinomas of the prostate that account for two separate entities in the WHO classification of prostate tumors.
Squamous cell carcinomas of the prostate are very rare and encompass <1% of prostat...
Urothelial carcinomas or transitional cell carcinomas of the prostate are malignant neoplasms that can occur as primary cancers of the prostate gland.
Prostatic urothelial carcinomas account for less than 2-4% of all prostate cancers 1 and are usually seen in middle-aged men 2.
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.
High-grade prostatic intraepithelial neoplasia (HGPIN) refers to a proliferation of glandular epithelial cells and is generally considered a nonobligatory precursor lesion of invasive prostate cancer.
High-grade prostatic intraepithelial neoplasia is diagnosed in core needle biops...
Intraductal carcinomas of the prostate (IDCP) are a new subtype of prostate cancer that has been included as a new entity in the WHO classification of prostate tumors in 2016.
Intraductal carcinomas of the prostate are rarely found isolated on needle core biopsy samples in 0.1-0.3...
Ductal adenocarcinomas of the prostate or prostatic ductal adenocarcinomas are malignant glandular neoplasms of the prostate and tend to be more aggressive than acinar adenocarcinomas.
Due to its morphologic resemblance, it has been formerly referred to as 'endometrial' or 'endomet...
Renal atrophy refers to a shrunken small appearance of the kidneys usually due to a secondary cause in contrast to renal hypoplasia which is the term given to a congenitally small kidney.
Renal atrophy can be unilateral or bilateral depending on the cause and when unilateral, the left kidney is...
Adenocarcinoma of the prostate with neuroendocrine differentiation is a malignant neuroendocrine tumor of the prostate which only differs from acinar or ductal adenocarcinoma on immunohistochemistry staining.
Adenocarcinoma of the prostate with neuroendocrine differentiation is an ac...
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.
Well-differentiated neuroendocrine tum...
Large cell neuroendocrine carcinomas (LCNEC) of the prostate or prostatic large cell neuroendocrine carcinomas are very aggressive and rare high-grade neuroendocrine tumors that are usually observed in the presence of an already existing adenocarcinoma and very rarely found alone.
Small cell carcinomas of the prostate (SCCP) or small cell neuroendocrine carcinomas of the prostate are neuroendocrine tumors and are characterized by aggressive behavior and a proliferation of small cells.
Small cell neuroendocrine carcinomas of the prostate are rare 1,2 and mak...
Flip-flop renal enhancement describes when an infarcted renal parenchyma alternates between hypoattentuation during the arterial phase, and hyperattenuation on the delayed phase of a contrast enhanced CT 1,2.
Flip-flop renal enhancement should not be confused with the flip-flop ef...
Prostate imaging recurrence reporting (PI-RR) or prostate MRI for local recurrence reporting is a structured reporting scheme similar to the Prostate Imaging-Reporting and Data System (PIRADS) v2.1 on multiparametric prostate MRI for the detection of local recurrence after radical prostatectomy ...
Acute non-traumatic abdominal pain in pregnancy requires a considered imaging approach due to the increased risks of fetal demise associated with undiagnosed diseases such as perforated acute appendicitis. Ultrasound is the first-line modality due to its wide availability and ability to diagnose...
Dialysis-related spondyloarthropathy is a relatively uncommon complication of renal dialysis. It is part of the spectrum of dialysis-related amyloidosis.
Thought to be mainly due to extensive deposition of beta-2 microglobulin (amyloid-like substance) within the spine (especially in...
CT of the adrenal glands is a study utilized in patients with incidentally discovered adrenal lesions on other studies, in order to characterize the lesions, and to seek adrenal abnormalities in patients with hormonal biochemical abnormalities.
Characterize incidentally discovered ...
Renal emphysema, or intrarenal gas, refers to the presence of gas within the kidney, with or without extension to the urinary tract.It is a rare finding and only a few differentials need to be considered 1:
emphysematous pyelonephritis 1
The Bosniak classification of cystic renal masses (version 2019), or usually simply Bosniak classification, version 2019, is a proposed update of the classic/current Bosniak criteria. The update hopes to improve on the classification's predictive power for malignancy and minimize the number of ...
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.
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 (male bladder)
History and etymology
Uvula is Latin for 'little ...
Granulomatous epididymitis refers to a form of epididymitis secondary to a granulomatous process. It may or may not be associated with concurrent orchitis.
It is usually associated with:
tuberculosis - tuberculous epididymitis
bacillus Calmette–Guérin (BCG) vaccine
Occasionally cases are idi...
A buried penis is a condition in which a normal sized penis is entrapped partially or completely by the surrounding subcutaneous fat and soft tissues of the scrotum, thighs, or hypogastrium.
congenital poor fixation of the penile skin at its base 3
Prostate MRI has become an increasingly frequent examination faced in daily radiological practice and is mainly conducted for the detection, active surveillance and staging of prostate cancer. This approach is an example of how to create a radiological report of a prostate MRI (usually mpMRI) wi...
The perineal body, also known as the central tendon of the perineum, (TA: corpus perineale) is a key midline fibromuscular structure, with important muscular attachments, which acts to stabilize the structures of the pelvis and perineum. It is located between the anal canal and the bulb of the p...
The transverse perineal muscles are important for the stability of the pelvic and perineal structures via their intimate relationship with the perineal body. For many years, it was thought that these muscles directly inserted into the perineal body. It is now known that fibers from the muscles o...
The paired deep transverse perineal muscles (TA: musculus transversus profundus perinei) lie in the perineum and are important for stabilizing the perineal body.
origin: ischial ramus
insertion: the fibers of each muscle meet in the midline at the perineal body and decussate to intert...
The paired superficial transverse perineal muscles (TA: musculus transversus superficialis perinei) lie in the perineum and are important for stabilizing the perineal body.
origin: ischial tuberosity
insertion: the fibers of each muscle meet in the midline at the perineal body and dec...
Cellular angiofibromas are benign densely vascularized fibroblastic neoplasms usually found in the lower genital tract specifically vulva, vagina or perineum in women and the scrotum or groin in men.
Cellular angiofibromas are rare tumors found in the adult population. There is no...
Seminal vesicle invasion (SVI) is referred to as the secondary involvement of the seminal vesicles and ductus (vas) deferens by neoplasms not originating from the seminal vesicles themselves and are much more common than their primary counterparts. Involvement of the seminal vesicles stages pros...
Seminal vesicle fusion is a congenital abnormality that refers to the midline fusion of the seminal vesicles.
This is a very rare anomaly that has been reported in some sporadic case series and case reports in infertile men 2.
Only one case desc...
Ejaculatory duct obstruction refers to the congenital or acquired obstruction of the ejaculatory ducts.
Ejaculatory duct obstruction is rare, accounting for approximately 5% of infertile patients, but thought to be underdiagnosed 2.
Patients may complain ab...
Seminal vesicle hypoplasia is a congenital anomaly that refers to the underdevelopment of one or both seminal vesicles.
All mesonephric duct maldevelopments may be observed:
seminal vesicle agenesis
seminal vesicle cysts
congenital agenesis of the ...
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...
Stromal tumor of uncertain malignant potential (STUMP) is a rare stromal tumor of the prostate with a broad spectrum of histologic patterns and variable clinical behavior.
Stromal tumor of uncertain malignant potential has been also known as atypical stromal hyperplasia, cystic epi...
Sarcomatoid carcinoma of the prostate is a rare malignant prostatic tumor variant usually composed of both malignant glandular cells and spindle cells.
Sarcomatoid carcinoma of the prostate is also known as carcinosarcoma, metaplastic carcinoma or spindle cell carcinoma of the pros...
Leiomyosarcoma of the prostate is a rare mesenchymal smooth muscle malignancy of the prostate gland.
It is a rare tumor with less than 200 cases reported in the literature accounting for approximately 25% of all sarcomas of the prostate gland and less than 0.1% of primary prostate...
Cystic dilatation of the seminal vesicles refers to dilatation to one or both seminal vesicles often occurring as a result of a downstream obstruction (atresia of the ejaculatory ducts or ectopic ureteral insertion into the seminal vesicles). On imaging it is seen as continuous dilatation to one...
Seminal vesicle agenesis is a condition that refers to the congenital absence of one or both seminal vesicles.
Seminal vesicle agenesis is a rare finding with a reported incidence of 0.08 % 2.
Developmental anomalies of the ipsilateral urogenital tract may be observ...
Watchful waiting, also known as watch and wait, describes a palliative management option with the main goal to maintain/improve quality of life, to control complications as well as minimize adverse treatment-related effects.
Watchful waiting is usually considered in elderly patients with...
Active surveillance describes a management option aiming at close monitoring of a specific stage in disease and minimizing adverse treatment-related effects without compromising survival at the same time. Curative or definite treatment is intended and offered upon deterioration or explicit patie...
Ureteral calcification refers to the presence of calcium concretions within the ureteral lumen or wall.
transitional cell carcinoma
schistosomiasis of the urinary tract
Thrombosis of the pampiniform plexus is a rarely reported phenomenon of the formation of thrombus within the pampiniform plexus of the testes. It may occur with or without a varicocele. Its exact etiology is not well known but has sometimes been seen following epididymo-orchitis 1. Spontaneous o...
Several normal anatomical structures and rare organ variants have been described as being horseshoe-shaped.
horseshoe pancreas 1
Cystic renal neoplasms comprise of a heterogeneous group of renal tumors. They can have variable biological profiles. They may be purely cystic or could be cystic with solid components, and they may be benign or malignant.
mixed epithelial and stroma...
The PSA velocity (PSAV) is a statistically-derived measure of how the prostate specific antigen (PSA) changes over time, and has been used as a marker of how prostate malignancy progresses or regresses.
Any cancer grows over time and relative changes of tumor markers, such as PSA, would seem t...
Percutaneous ablation in the kidney is now performed as a standard therapeutic nephron-sparing option in patients who are poor candidates for resection. It is performed via radiofrequency ablation or cryoablation.
Follow-up time frame
Can vary according to center but usually includes contrast-...
Intrapelvic cup migration is a serious complication after total hip arthroplasty, in which the prosthetic acetabular cup migrates or drifts into the pelvic inlet.
Fortunately, this complication is very rare. There seems to be a female predisposition 1-3.
Male infertility is the inability to conceive due to factors in the male partner.
Precise numbers vary but generally, male factor is estimated to play a role in up to half of infertility cases 3.
Causes of male infertility can be considered as:
pre-testicular, e.g. h...
Autonephrectomy refers to the end stage of renal tuberculosis where chronic tuberculous infection causes caseous necrosis and progressive renal cavitation, rendering the kidney non-functioning 1.
It is a rare occurrence in non-endemic populations today but can be misdiagnosed if n...
The saddlebag bladder sign refers to the appearance caused on axial pelvic MR images by posterior drooping of the posterolateral wall(s) of the urinary bladder, due to loss of integrity of the lateral level 2 endopelvic fascia. If combined with a defect of the puborectalis muscle on the ipsilate...
The drooping moustache sign refers to the appearance caused on axial pelvic MR images by posterior prolapse of the fat in the retropubic space, akin to the drooping corners of a moustache, due to loss of integrity of the urethral suspensory ligaments and level 3 endopelvic fascia.