Cystinosis, also known as Abderhalden Kaufmann Lignac syndrome, is the most common hereditary cause of renal Fanconi syndrome. Cystinosis is one of the lysosomal storage disorders.
It has a reported incidence of 1:192,000 1. Cystinosis is typically diagnosed in infancy.
Dacryocystoceles are caused by obstruction of both the proximal and distal ends of the nasolacrimal duct. An imperforate Hasner valve causes the distal blockage, but the cause of proximal obstruction is less clearly understood but the Rosenmuller valve has been implicated.
Dandy-Walker continuum, also referred as Dandy-Walker spectrum or Dandy-Walker complex, corresponds to a group of disorders believed to represent a continuum spectrum of posterior fossa malformations, characterized by inferior vermian hypoplasia and incomplete formation of the fourth ventricle w...
Danon disease is an X-linked dominant cause of debilitating cardioskeletal myopathy and is a lysosomal storage disorder.
Although considered rare, the exact incidence is unknown 1.
Danon disease is characterized by the triad of 1-4:
A generalized retardation in skeletal maturation has different causative or etiological factors, these can be classified as follows:
chronic ill health
congenital heart disease (especially cyanotic)
chronic renal disease
inflammatory bowel disease
malnutrition: failure to thrive (FTT)
The Delbet classification helps predict the risk of avascular necrosis of the femoral head in neck of femur fractures, as well as determine operative vs non-operative management.
type I: trans-epiphyseal separation
fracture through proximal femoral physis, and represents Salte...
The delta resistive index (delta RI or Δ RI) is a measurement that can be made when performing Doppler ultrasound.
In preterm babies who have hydrocephalus secondary to intraventricular hemorrhage, the delta RI can be used to determine whether decompression of the ventricular system with an...
The differential diagnosis of dense metaphyseal bands is wide.
chronic anemia, e.g. sickle cell disease, thalassemia
chemotherapy, e.g. methotrexate
growth acceleration lines following growth arrest due to systemic illness or stress in infancy or childhood, e.g...
Desmoplastic infantile astrocytoma and gangliogliomas are a rare intracranial tumor, which despite their aggressive appearances tend to have a good prognosis and are considered WHO grade I tumors.
Previously considered separate entities, desmoplastic infantile astrocytoma and desm...
Developmental dysplasia of the hip (DDH), or in older texts congenital dislocation of the hip (CDH), denotes aberrant development of the hip joint and results from an abnormal relationship of the femoral head to the acetabulum.
Unlike CDH, developmental dysplasia of the hip is not confined to c...
Diabetic embryopathy refers to a spectrum of fetal anomalies that precipitate when the mother has background type I diabetes mellitus. The fetus may develop many of the fetal conditions associated with maternal diabetes although strictly speaking the anomalies should only include those that star...
Diamond-Blackfan anemia (DBA) (previously known as congenital hypoplastic anemia) is the primary congenital form of pure red cell aplasia. It is a rare sporadic genetic form of anemia that typically presents in the first few years of life, and usually only affects cells of the erythroid lineage ...
Diastasis recti (rectus diastasis) or divarication of the recti is a stretching of the linea alba with abnormal widening of the gap between the two medial sides of the rectus abdominis muscle (increased inter-recti distance).
The degree of widening needed for the diagnosis is controversial, wit...
Diastematomyelia, also known as a split cord malformation, refers to a type of spinal dysraphism (spina bifida occulta) when there is a longitudinal split in the spinal cord.
Although traditionally it has been distinguished from diplomyelia (in which the cord is duplicated rather ...
DICER1 syndrome is a rare autosomal dominant disorder predisposing individual to the development of multiple tumor types. DICER1 is considered a tumor suppressor gene that encodes the endoribonuclease protein Dicer. The first association with pleuropulmonary blastoma was discovered in 2009.
Diffuse brainstem gliomas, also known as diffuse intrinsic brainstem glioma (DIBG), is a term used to describe infiltrating astrocytomas, no longer recognized as a distinct entity in the 2016 update to the WHO classification of CNS tumors. It encompassed a variety of tumors, ranging from WHO gra...
Disorder of gender development refers to the spectrum of rare congenital conditions in where there is an atypical development of chromosomal, gonadal, or anatomic sex.
They can be classified broadly into four categories on the basis of gonadal histologic features which include:
Divry van Bogaert syndrome is a familial juvenile-onset syndrome characterized by livedo racemosa, juvenile ischemic stroke, juvenile cerebral white matter disease leading to premature dementia, and epilepsy.
juvenile ischemic stroke
early-onset cognitive impai...
Dorsal brainstem syndrome is a rare subset of hypoxic ischemic encephalopathy in neonates limited to the isolated involvement of the brainstem with sparing of the supratentorial brain. Due to its subtle imaging features it is often undiagnosed.
Injuries involving the tegm...
The double bubble sign is seen in infants and represents dilatation of the proximal duodenum and stomach. It is seen in both radiographs and ultrasound, and can be identified antenatally 2.
Causes include 1,2:
The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma.
It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim.
The double lung point sign refers to a sharp boundary found between relatively aerated superior lung fields and coalescent "B‐lines" (representing interstitial edema) in the basal lung fields, with a reported sensitivity of 45.6%-76.7% and a specificity of 94.8%-100% 1,3 in diagnosing transient ...
Double outlet left ventricle (DOLV) is an extremely rare congenital cardiac anomaly where both the aorta and pulmonary trunk arise from the anatomical left ventricle. It is usually classified as a conotruncal anomaly and is often associated with a ventricular septal defect with normal continuity...
Double outlet right ventricle (DORV) is a congenital cardiac anomaly where both the aorta and pulmonary trunk arise from the morphologically right ventricle. It is reported to account for ~2% of congenital cardiac defects 1. It is usually classed as a conotruncal anomaly. There is almost always ...
The double track sign is a radiological sign described in pyloric stenosis on various imaging modalities.
Double streaks of barium passing through the narrow pylorus 1.
On fluid aided real-time examination, the pyloric fluid is compressed into smaller tracks as it is...
The doughnut sign can refer to a variety of different signs:
doughnut sign (bone scan)
doughnut sign (bowel)
crescent in a doughnut sign (bowel)
doughnut sign (orbit)
Drash syndrome, also known as the Denys-Drash syndrome, is associated with an abnormal WT1 gene (Wilms tumor gene) and consists of:
Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a rare form of epilepsy usually presenting in the first 1-2 years of life.
The typical presentation occurs during the first six months to one year of life as tonic-clonic seizures in a fe...
Duane radial ray syndrome (DRRS) (also known as the Okihiro syndrome) is a rare an autosomal dominant condition characterized by radial ray defects and a Duane anomaly (a form of strabismus with horizontal gaze palsy).
Duane syndrome, also known as Duane retraction syndrome, is a rare congenital disease characterized by non-progressive strabismus. It is caused by a variable degree of abnormal development of one or both 6th cranial nerves (CN VI).
It presents during childhood and it accounts for ...
Dubowitz syndrome (DS) is a rare genetic disorder with a wide clinical spectrum which includes:
intrauterine growth restriction (IUGR)
postnatal growth restriction
moderate intellectual disability
characteristic facial anomalies
Duchenne muscular dystrophy (DMD) is a dystrophinopathy and the most common muscular dystrophy.
DMD has an incidence of 1 in 3500 to 5000 males 1,2. The condition is extremely rare in females due to its inheritance pattern, as discussed below 1.
The ductus arteriosum (DA) (or arteriosus) is the thick short conduit for blood to bypass the non-ventilated lungs in the fetus. It is located between and connects the proximal left pulmonary artery and the undersurface of the aortic arch distal to the origin of the last branch of the arch, at t...
Ductus venosus (DV) is a narrow, trumpet-shaped vessel which is seen in the fetal liver connecting the umbilical vein directly to the caudal inferior vena cava. The vessel plays a critical role in the fetal circulation by shunting oxygenated and nutrient-rich umbilical venous blood from the plac...
Duodenal atresia results from a congenital malformation of the duodenum and requires prompt correction in the neonatal period. It is considered to be one of the commonest causes of a fetal bowel obstruction.
The prevalence of duodenal atresia is ~1 in 5,000-10,000 newborns, and th...
A duodenal web, diaphragm or intraluminal diverticulum refers to a complete or incomplete obstruction at the duodenum due to a membranous web or intraluminal diverticulum. There is usually a small aperture at the center differentiating this from a duodenal atresia.
Although they are frequently...
Dysgenesis of the corpus callosum may be complete (agenesis) or partial and represents an in utero developmental anomaly. It can be divided into:
primary agenesis: the corpus callosum never forms
secondary dysgenesis: the corpus callosum forms normally and is subsequently destroyed
Dysplasia epiphysealis hemimelica (DEH), also known as Trevor disease, is an extremely rare, non-hereditary disease that is characterized by osteochondromas arising from the epiphyses.
The incidence is estimated at ~1:1,000,000 3. There is a recognized male predilection (M:F = 3:1...
Ebstein anomaly is an uncommon congenital cardiac anomaly, characterized by a variable developmental anomaly of the tricuspid valve.
The anomaly accounts for only ~0.5% of congenital cardiac defects 6,7, although it is the most common cause of congenital tricuspid regurgitation. T...
Echogenic fetal bowel is an observation in antenatal ultrasound imaging, in which fetal bowel appears to be brighter than it is supposed to be. It is a soft marker for trisomy 21 and has several other associations. When observed, it needs to be interpreted in the context of other associated abno...
Ectodermal dysplasia (ED) refers to a heterogeneous group of genetic disorders that cause abnormal ectoderm development. The effect is a non-progressive defect in the development of two or more tissues derived from embryonic ectoderm.
ED is rare with an estimated prevalence of 1:...
Ectopia cordis is an extremely rare congenital malformation where the heart is located partially or totally outside the thoracic cavity. The four main ectopic positions are:
adjacent to the thorax: ~60%
The incidence is ...
An ectopic ureter is a congenital renal anomaly that occurs as a result of abnormal caudal migration of the ureteral bud during its insertion to the urinary bladder. Normally the ureter drains via the internal ureteral orifice at the trigone of the urinary bladder.
In females, the most common ...
Ectrodactyly-ectrodermal dysplasia-clefting (EEC) syndrome is a rare genetic syndrome that has high clinical variability but typically comprises of the triad of
ectrodactyly +/- syndactyly 1 +/- polydactyly 5
facial clefts: cleft lip and/or palate
Edwards syndrome, also known as trisomy 18, along with Down syndrome (trisomy 21) and Patau syndrome (trisomy 13), make up the only three autosomal trisomies to be compatible with extrauterine life in non-mosaic forms, albeit in the case of Edward syndrome only for a week or so.
Egg-on-a-string sign, also referred to as egg on its side, refers to the cardiomediastinal silhouette seen in transposition of the great arteries (TGA).
The heart appears globular due to an abnormal convexity of the right atrial border and left atrial enlargement and therefore appears like an ...
The Eisenmenger syndrome is a complication of an uncorrected high-flow, high-pressure congenital heart anomaly leading to chronic pulmonary arterial hypertension and shunt reversal.
In general, the shunts that lead to Eisenmenger syndrome share high pressure and high flow 3. As su...
Elbow ossification occurs at the six elbow ossification centers in a reproducible order. Being familiar with the order of ossification of the elbow is important in not mistaking an epicodylar fracture for a normal ossification center.
The order of appearances of the elbow os...
Mnemonics for elbow ossification include CRITOE and CRITOL. These are essentially the same, apart from the terminal letter which represents the External or Lateral epicondyle.
R: radial head
I: internal epicondyle
E: external epicon...
The embryonal subtype of rhabdomyosarcoma is the most common variety of rhabdomyosarcoma, accounting for 50-70% of cases 1-2. It is typically seen in children below the age of 15.
Embryonal rhabdomyosarcomas are further divided into three sub types 1:
spindle cell rhabdomyosarcoma
Embryonal tumors with multilayered rosettes (ETMR) are rare small round blue cell tumor of the central nervous system and are one of the most aggressive brain tumors usually encountered in children.
Previously embryonal tumors with multilayered rosettes (ETMR) were known as embryo...
Encephalocele, also known as meningoencephalocele, is a form of neural tube defect and a type of cephalocele where brain tissue and overlying meninges herniate out through a defect in the cranium.
It should be distinguished from cranial meningocele in which the lesion contains onl...
Encephaloduroarteriomyosynangiosis (EDAMS) is a surgical procedure performed most commonly in children with moyamoya disease or less commonly in individuals with intracranial atherosclerotic disease as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or ...
Encephalomyosynangiosis (EMS) is a surgical procedure performed most commonly in children with moyamoya disease as a form of indirect revascularization to bypass the occlusive terminal internal carotid and/or circle of Willis vessels 1.
It entails dissecting strips of vascularized temporalis m...
Enchondromatosis, also known as Ollier disease (see Terminology section), is a non-hereditary, sporadic, skeletal disorder characterized by multiple enchondromas principally located in the metaphyseal regions.
Some authors make a distinction between Ollier disease and enchondromato...
Endocardial fibroelastosis (EFE) is a rare cardiac condition which is classically described in the pediatric population (typically first two years). It is one of the causes for infants to present with unexplained heart failure.
The condition results from increasing amounts of fibrou...
Endochondral ossification describes the process of ossification from mesenchymal cells (stem cells) with a cartilaginous template and is involved in the healing process of fractures.
Bone formation occurs at centers of ossification (or ossification centers) which are either primary or secondary...
Enterovirus 71 is one of the viruses that causes hand-foot-and-mouth disease in children. It is an enterovirus, one of the picornaviruses.
Infection with enterovirus 71 predominantly results in a vesicular rash of the hands and feet that follows a prodrome of symptoms including fever, vomiting ...
Enterovirus rhombencephalitis is the most common neurological complication of enterovirus infection 1.
Enterovirus rhombencephalitis causes acute and severe neurologic disorders such as ataxia, nystagmus, oculomotor palsies, or bulbar palsy. In some cases, neurologic affe...
Ependymoma RELA fusion-positive is a recently accepted molecular variant of ependymoma, only recognized in the 2016 update to the WHO classification of CNS tumors. They are the most common type of supratentorial ependymoma in children, and not found in the posterior fossa or spinal cord.
Epicondyle fractures are common injuries in children. They represent 10% of all elbow fractures in children and usually occur in boys after a fall on an outstretched arm.
Medial epicondyle fractures comprise most of these injuries. They can usually be treated with splinting and early physiother...
Epiglottitis is a life-threatening condition caused by inflammation of the epiglottis and aryepiglottic folds 1, which can lead to acute airway obstruction. Treatment should be urgent and performed by appropriately trained individuals, e.g. instrumentation of the trachea should be performed by ...
Episodic spontaneous hypothermia with hyperhidrosis syndrome (ESHH) is a rare syndrome characterized by periodic hypothermia and hyperhidrosis. This occurs in the absence of agenesis of the corpus callosum, thus differentiating it from Shapiro syndrome 1.
Episodic spontaneous hypo...
Epispadias is a rare congenital anomaly that is almost always associated with bladder exstrophy.
It occurs in 1 in 30,000 births, with a male: female ratio of 3:1.
The roof of the urethra is absent and the urethra opens anywhere between the base and the gl...
Erb palsy, also known as brachial plexus birth palsy, is a form of obstetric brachial plexus injury as a result of complications during delivery.
The most common cause is due to excessive lateral traction or stretching of the fetal head and neck in opposite directions du...
Endotracheal tubes (ETT) are wide-bore plastic tubes that are inserted into the trachea to allow artificial ventilation. Tubes come in a variety of sizes and have a balloon at the tip to ensure that gastric contents are not aspirated into the lungs. Adult tubes are usually approximately 1 cm in ...
Ewing sarcomas are the second most common malignant primary bone tumors of childhood after osteosarcoma, typically arising from medullary cavity with invasion of the Haversian system. They usually present as moth-eaten destructive permeative lucent lesions in the shaft of long bones with large s...
The Ewing sarcoma family of tumors are a group of small round blue cell tumors that are closely histogenetically related, all demonstrating non-random t(11;22)(q24;q12) chromosome rearrangement resulting in the formation of the EWS-ETS fusion gene 1-3.
Although the literature is l...
External beam radiotherapy (EBRT) (also known as teletherapy) is a form of ionizing radiation therapy delivered by a medical linear accelerator (or historically a cobalt-60 source) to a patient lying on a treatment bed. Megavoltage x-rays (4-25 MV) are the most commonly used. Alternative forms o...
Extracorporeal membrane oxygenation (ECMO) is used as a modified pulmonary or cardiopulmonary bypass technique in those with severe cardiac and/or respiratory failure refractory to conventional ventilatory support and medical intervention 1,3. There are two access paths for extracorporeal life s...
The extrusion index is a radiographic measurement of femoral head bony coverage by the acetabulum. It is useful in assessing for developmental dysplasia as well as femoroacetabular impingement.
It is calculated by dividing the horizontal distance of the lateral femoral head that is uncovered by...
Exudative retinitis, also known as retinal telangiectasis or Coats disease, is a rare congenital disease affecting the eyes and is a cause of leukocoria.
It occurs predominantly in young males, with the onset of symptoms generally appearing in the first decade of life with a peak ...
Facioscapulohumeral muscular dystrophy (FSHD) is a form of muscular dystrophy characterized by extremely variable degrees of facial, scapular and lower limb muscle involvement.
It is considered one of the more common hereditary muscular disorders with a prevalence of ~1 in 8,000.
Familial adenomatous polyposis syndrome (FAPS) is characterized by the presence of hundreds of adenomatous polyps in the colon. It is the most common of the polyposis syndromes.
Familial polyposis coli, attenuated familial adenomatous polyposis and Gardner syndrome are all variants...
Familial Mediterranean fever (FMF) (also known as recurrent polyserositis) is a genetic autoimmune condition that is notable for its spontaneous self-limiting acute episodes of fever and serositis, especially peritonitis and synovitis.
Familial Mediterranean fever tends to be ethn...
Fatco syndrome is a syndrome consisting of
tibial campomelia and
It is a syndrome of unknown genetic basis and inheritance with variable expressivity and penetrance.
Fuhrmann syndrome and Al-Awadi syndrome are said to be similar to FA...
Faulty fetal packing, also known as congenital vault depression, is a congenital concave depression of the skull in a newborn.
Occurs in 1 in 10,000 births 1.
This appearance is due to external compression on the skull from 1,2:
fetal limb or twin
Febrile infection-related epilepsy syndrome (FIRES) is a severe postinfectious neurological disorder that presents with status epilepticus in a previously normal child (or less commonly adult) after a febrile illness.
FIRES has received several names in the literature:
Feingold syndrome is characterized by the combination of:
alimentary tract atresias especially esophageal atresia
Femoral facial syndrome, also known as femoral hypoplasia-unusual facies syndrome, is a rare congenital syndrome characterized by varying degrees of femoral hypoplasia and facial dysmorphism 1.
Femoral facial syndrome can cause varying degrees of femoral malformation rang...
Femur sparing intrauterine growth restriction is considered by some authors as a particular type of intrauterine growth restriction (IUGR) 1. In this type, the femoral length is the only standard fetal biometric parameter unaffected while all others are reduced.
Fetal circulation differs from the adult circulation due to the presence of certain vessels and shunts.
These shunts close after birth, and most of the fetal vessels are visible as remnants in the adult circulation. The function of these shunts is to direct oxygen-rich venous blood to the syst...
Fetal congenital complete heart block (CAVB) is a rare cardiac conduction abnormality that is associated with high morbidity and mortality. It is considered the commonest of fetal bradyarrhymias.
The estimated prevalence of complete heart block in newborns is at ~1 in 20,000.
Fetal lung interstitial tumor (FLIT) is a recently proposed designation for a rare primary lung mass detected prenatally or when the patient is up to 3 months old.
Fetal lung interstitial tumors have a slight predominance in boys 1.
Fetal lung interstitial tumors were ...
A fetal orbital mass is a rare occurrence but can arise from many patholologies
The list includes
Tumourous orbital masses
fetal orbital teratoma
Non tumourous orbital masses
orbital encephalocoele 2
orbital heterotopic brain tissue 1
congenital cystic eyeball 4
Tricuspid regurgitation (TR) (also known as tricuspid insufficiency) is a common finding in imaging of the fetus. Tricuspid regurgitation represents the abnormal backflow of blood into the right atrium during right ventricular contraction due to valvular leakage (i.e. it is a valvulopathy).
Although rare, a number to tumors may be diagnosed antenatally. These fetal tumors are a diverse and a unique group of conditions, and include:
neuroblastoma: most common tumor overall
head and neck teratoma/epignathus
Fetus-in-fetu is an extremely rare abnormality that occurs secondary to abnormal embryogenesis in a monochorionic diamniotic pregnancy where a non-viable fetus becomes enclosed within a normally developing fetus.
Fetus-in-fetu is very rare, with an incidence of 1/500,000 live birt...
Fibrodysplasia ossificans progressiva (FOP), previously known as myositis ossificans progressiva (MOP) and also known as Munchmeyer’s disease, is a rare, inherited disorder characterized by progressive fibrosis and ossification of muscles, tendons, fasciae, aponeuroses, and ligaments of multiple...
Fibromatosis colli is a rare form of infantile fibromatosis that occurs within the sternocleidomastoid muscle.
There may be a slight male predilection. It typically presents a few weeks after birth.
Presentation is usually with torticollis and is most frequ...
Fibrosing colonopathy a condition characterized by progressive submucosal fibrosis, particularly of the proximal colon. It is associated with high dose lipase supplementation used to treat exocrine insufficiency of the pancreas, such as in treatment for cystic fibrosis.
It is more...
Fibrous cortical defects (FCD) are benign bony lesions and are a type of fibroxanthoma, histologically identical to the larger non-ossifying fibroma (NOF).
Fibrous cortical defects typically occur in children (usually 2-15 years), and indeed are one of the most common benign bony ...
Fibrous dysplasia (FD) is a non-neoplastic tumor-like congenital process, manifested as a localized defect in osteoblastic differentiation and maturation, with the replacement of normal bone with large fibrous stroma and islands of immature woven bone. Fibrous dysplasia has a varied radiographic...