Pectus excavatum (or funnel chest) is a congenital chest wall deformity characterised by concave depression of the sternum, resulting in cosmetic and radiographic alterations.
It is the most common chest wall deformity, accounting for approximately 90%, and occurs in up to 1 in 30...
Pelvic osteotomy relates to an orthopaedic treatment for developmental acetabular dysplasia of the hip.
The main purpose of pelvic osteotomy is the prevention of early degenerative changes by stabilisation of the hip and redistribution of joint loading. It is obtained by surgical re-shaping/ re...
PELVIS or LUMBAR syndrome is the combination of pelvic haemangiomas with other extracutaneous abnormalities. The syndrome may be incomplete.
external genital malformations
Pelvi-ureteric junction (PUJ) obstruction/stenosis, also known as ureteropelvic junction (UPJ) obstruction/stenosis, can be one of the causes of an obstructive uropathy. It can be congenital or acquired with a congenital PUJ obstruction being one of the commonest causes of antenatal hydronephros...
The pentalogy of Cantrell is an extremely rare phenomenon with an incidence estimated at around 6 per million live births 3.
It encompasses the following 5 main features 1.
ectopia cordis (abnormal location of heart)
pericardial defect or sternal cleft
The pentalogy of Fallot is a variant of the more common tetralogy of Fallot, comprising the classical four features with the addition of an atrial septal defect or patent ductus arteriosus The five features therefore are:
ventricular septal defect (VSD)
right ventricular outlfow tract narro...
Pepper syndrome is of interest only (the term is not readily used in day-to-day practice), and refers to primary adrenal neuroblastoma with extensive liver metastases 1. In essence, it refers to stage 4S neuroblastoma (see staging of neuroblastoma).
Pericallosal lipomas are fat-containing lesions occurring in the interhemispheric fissure closely related to the corpus callosum, which is often abnormal. It is the most common location for an intracranial lipoma.
On imaging, they can be identified in two different morphologies: tubulonodular, ...
Perinatal lethal hypophosphatasia (PLH) is the most severe form of hypophosphatasia. If untreated, it is lethal in all cases.
The estimated incidence is at ~1:100,000 live births.
As with all hypophosphatasia cases, this is due to a mutation in chromosome 1q3...
Periosteal reaction in the paediatric population, also known as periostitis in children, is relatively common occurrence and can result from many causes.
The differential diagnosis for multiple bone periostitis include but not limited to the following:
Peripheral primitive neuroectodermal tumors (pPNET) tend to be large and agressive retroperitoneal tumours.
The imaging characteristics of peripheral PNETs is nonspecific. However, they should be considered in the differential diagnosis for an large, aggressive retroperitoneal mass.
Periventricular leukomalacia (PVL) or white matter injury of prematurity affecting the periventricular zones, and typically results in cavitation and periventricular cyst formation.
It is important to note that both periventricular and subcortical leukomalacia correspond to a continuous diseas...
One of the methods used for grading of periventricular leukomalacia based on sonographic appearances is as:
grade 1: areas of increased periventricular echogenicity without any cyst formation persisting for more than 7 days
grade 2: the echogenicity has resolved into small periventricular cyst...
Perkin line is a line drawn perpendicular to Hilgenreiner line, intersecting the lateral most aspect of the acetabular roof.
The upper femoral epiphysis should be seen in the inferomedial quadrant: it should lie below Hilgenreiner line, and medial to Perkin line. If the nucleus of the femoral ...
Persistent hyperplastic primary vitreous (PHPV), also known as the persistent fetal vasculature, refers to a rare congenital developmental malformation of the eye.
Clinically, this condition usually manifests as unilateral or bilateral leucocoria. Patients may also have p...
Perthes disease (also referred to as Legg-Calvé-Perthes disease) refers to idiopathic avascular necrosis (AVN) of the femoral epiphysis seen in children. It should not be confused with Perthes lesion of the shoulder.
It is a diagnosis of exclusion and other causes of avascular necrosis (includi...
Perthes disease is the name given to idiopathic AVN (avascular necrosis) of the femoral epiphysis in children. It most often occurs in children around the age of 5-6 years and is one of the common considerations when children present with an atraumatic limp or hip pain.
PHACE syndrome, also known as cutaneous haemangioma–vascular complex syndrome or Pascual-Castroviejo type II syndrome, is a phakomatosis that comprises of:
P: posterior fossa malformations (e.g. Dandy-Walker malformation)
A: arterial anomalies
C: coarctation of the aorta and ...
Phenylketonuria (PKU) is an inborn error of metabolism resulting from abnormal metabolism of phenylalanine. If untreated, patients can develop central nervous system impairment.
PKU is inherited as an autosomal recessive disorder with an incidence of 1 in 10,000. It is more commo...
Physeal bars are interruptions of the normal growth plate cartilage, due to the formation of a bony or fibrous bridge between the epiphysis and metaphysis. Left untreated, physeal bars can cause abnormal bone angulation or limb length discrepancies.
Physeal bars are not ...
Physeal fractures (also called Salter-Harris fractures) are important childhood fractures that involve the physeal plate. They are relatively common and important to differentiate from other injuries because the involvement of the physis (growth plate) may cause premature closure resulting in li...
Pilocytic astrocytomas, also known as juvenile pilocytic astrocytomas, are low-grade, relatively well-defined astrocytomas that tend to occur in young patients. They are considered WHO grade I tumours in the current (2016) WHO classification of CNS tumours and correspondingly have a relatively g...
Ping pong skull fracture or pond skull fracture refers to a depressed skull fracture of the infant skull caused by inner buckling of the calvarium. It is seen in newborns because of the soft and resilient nature of their bones (like greenstick fractures of long bones) and the fracture line is no...
Pink tetralogy of Fallot refers to a tetralogy of Fallot in which the degree of right ventricular outflow is minimal, resulting no significant right to left shunt, and therefore no cyanosis. Symptoms are mild and presentation may be delayed, even into adulthood.
tetralogy of Fallot
Plagiocephaly refers to a type of craniosynostosis in which there is an asymmetric coronal and/or lambdoid sutures premature closure. It can either be single or asymmetric multiple. Premature coronal suture closure is associated with the Harlequin eye deformity.
Platyspondyly is a radiographic feature and refers to flattened vertebral bodies throughout the axial skeleton.
Platyspondyly can be feature of many conditions which include:
severe Gaucher disease 1
Pleuropulmonary blastomas (PPB) are rare, variably aggressive, childhood primary intrathoracic malignancy. In up to 25% of cases, the mass can be extrapulmonary with attachment to the parietal pleura.
PPB is encountered in childhood, mostly in the first years of life (90% in thos...
Pneumatosis coli is a descriptive sign presenting radiographically as intramural gas limited to the colonic wall.
There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cystoides intestinalis. Pneumatosis in...
Porencephaly is a rare congenital disorder that results in cystic degeneration and encephalomalacia and the formation of porencephalic cysts. The term is used variably among radiologists with its broadest definition being a cleft or cystic cavity within the brain 9, and its more narrow definitio...
Positional plagiocephaly, also known as deformational plagiocephaly, refers to a calvarial deformation that results from external pressure after birth when an infant is consistently placed in the same position for rest and sleep. It can be marked in very premature infants, whose heads become fla...
Posterior fossa astrocytomas, those arising either from the cerebellum or from the brainstem are most frequently seen in children. Approximately 60% of all paediatric astrocytomas are found in the posterior fossa (20% brainstem, 40% cerebellum).
Many types of astrocytoma are found in the poster...
Posterior urethral valves (PUVs), also referred as congenital obstructing posterior urethral membranes (COPUM), are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy.
Posterior urethral valves are congenital and only...
The Potter sequence is a constellation of findings demonstrated postnatally as a consequence of severe, prolonged oligohydramnios in utero.
It consists of
pulmonary hypoplasia: often severe and incompatible with life
growth restriction (IUGR)
abnormal facies (Potter fa...
A helpful mnemonic to remember the common clinical features of Potter syndrome:
P: pulmonary hypoplasia
T: twisted skin (wrinkly skin)
T: twisted face (Potter facies: low set ears, retrognathia, hypertelorism)
E: extremity deformities (limb deformities: club hands...
Pott puffy tumour refers to a non-neoplastic complication of acute sinusitis characterised by a primarily subgaleal collection, also subperiosteal abscess and osteomyelitis. It is usually related to the frontal sinus but sometimes also related with the mastoid. Forehead swelling is seen, which i...
A Pott shunt is a form of palliative surgery performed in patients with tetralogy of Fallot prior to the ability to repair the defect. It consists of a shunt formed between the descending thoracic aorta and the left pulmonary artery.
This does not relieve the right ventricular outflow obstructi...
Prader-Willi syndrome (PWS) is a rare genetic disorder. It is the most common cause of obesity caused by a genetic syndrome and is primarily characterised by:
sexual infancy: hypogonadism
there usually morbid obesity resulting from hyperphagia is amplified by decre...
Pre-axial polydactyly refers to polydactyly where the additional digit is towards the first digit of the hand (radial side) or foot (medially).
Pre-axial polydactyly is less common than post-axial polydactyly, with an estimated incidence of 1 in 7000.
Premature closure of a growth plate subsequently results in a shortened bone, which can occur in a number of situations.
juvenile chronic arthritis
juvenile rheumatoid arthritis
Prenatal onset infantile cortical hyperostosis is a rare variant of infantile cortical hyperostosis; however, it is a more severe and lethal form and newborns die early postnatally.
Both sporadic and autosomal recessive inheritance have been suggested.
A missense mutation in gene (C...
Primary ciliary dyskinesia (also known as immotile cilia syndrome) is the result of a congenital defect in the ultrastructure of cilia that renders them incapable of normal movement. It is associated with a number of anatomic and functional abnormalities.
Primary ciliary dyskinesi...
Primitive neuroectodermal tumours (or CNS PNET) were considered aggressive neoplasms of the brain, most frequently encountered in the paediatric population. Importantly, the term no longer appears in the current WHO classification of CNS tumours 11-12.
Please refer to embryonal tumours with mu...
Proteus syndrome is a rare congenital, multisystemic, hamartomatous condition characterised by asymmetrical overgrowth of almost any part of the body and a broad spectrum of manifestations. It can affect tissue from any germinal layer. It is suspected to be a genetic condition, but a particular ...
Proximal femoral focal deficiency (PFFD) is a congenital partial absence of the proximal end of the femur with shortening of the entire lower limb. The diagnosis and classification have been based mainly on plain radiograph findings. This method does not permit definite classification during the...
A proximal radio-ulnar synostosis is an upper limb skeletal malformation characterised by bony fusion at the proximal aspect of the radius and ulna. Of the radio-ulnar synostoses, the proximal third is considered the most common site.
It is often congenital but can rarely result fol...
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 ureteric dilatation
anterior abdominal wall underdevelopment (resulting in the "prune belly" appearance)...
Pseudocysts of the germinal matrix can be present at birth in both pre-term and full-term infants and may be due to a variety of pathologic disorders, frequently occur following haemorrhage, but they are also found incidentally in otherwise normal infants.
They are defined as pseudocysts becaus...
Pseudosubluxation of the cervical spine is the physiological anterior displacement of C2 on C3 in children. It is common in children <7 years, and less often present in older children. Less often it is seen at C3 on C4. It is more pronounced in flexion and is of clinical significance as it can b...
Pulled elbow (also known as nursemaid's elbow) is a subluxation of the radial head into the annular ligament, which usually spontaneously or easily reduces and rarely demonstrates abnormal radiographic features. It should be distinguished from dislocation of the radial head.
Pulmonary aplasia is a rare congenital pathology in which there is unilateral or bilateral absence of lung tissue. It is distinguished from pulmonary agenesis, although similar, the main difference being that there is a short-blind ending bronchus in aplasia 3.
It is usually unilateral, as bila...
Pulmonary artery atresia (or sometimes known as pulmonary atresia) is one of congenital cardiovascular anomaly in which there is complete disruption between the right ventricular outflow tract (RVOT) and the pulmonary trunk.
The estimated incidence is 1 in 10,000 births.
Pulmonary atresia with intact interventricular septum (PA-IVS) is a subtype of pulmonary atresia that presents as cyanotic congenital heart disease.
PA-IVS is the combination of obstruction of the pulmonary outflow tract from pulmonary valve atresia without a ventricular septal defe...
Pulmonary hypoplasia (PH) refers to deficient or incomplete development of parts of the lung. It can develop as a result of a number of other in-utero anomalies.
The true prevalence is not well known (1.4% of all births according to Knox et.al 13), but in cases of premature ruptur...
Pulmonary interstitial emphysema (PIE) refers to the abnormal location of air within the pulmonary interstitium and lymphatics. It typically results from rupture of overdistended alveoli following barotrauma in infants who have hyaline membrane disease. Interstitial emphysema can also occasional...
Pulmonary lymphangiectasia (PL) refers to a rare, fatal congenital abnormality of the lungs characterised by grossly dilated lymphatic channels in the sub pleural, interlobar, perivascular and peribronchial areas 3.
It is divided into two main types 1:
cardiac-associated lymphangiectasia (seco...
Pulmonary plethora is a term used to describe the appearances of increased pulmonary perfusion on chest radiographs. It is commonly used in paediatric radiology.
Usually a left-to-right shunt of 2:1 is required for pulmonary plethora to occur 2,3. Increased pulmonary perfusion occur...
Pulmonary sequestration, also called accessory lung, refers to the aberrant formation of segmental lung tissue that has no connection with the bronchial tree or pulmonary arteries. It is a bronchopulmonary foregut malformation (BPFM).
There are two types:
intralobar sequestration (ILS)
Extralobar pulmonary sequestration (ELS) is a subtype of pulmonary sequestration, the other type being intralobar pulmonary sequestration (ILS).
It is usually encountered in infants, most being diagnosed before six months. It is more common in male (M:F 4:1).
Intralobar pulmonary sequestration (ILS) is a subtype of pulmonary sequestration.
Patients usually present before the third decade with recurrent infection.
It is the commoner type of pulmonary sequestration (four times commoner than extralobar sequestration),...
Pyknodysostosis, also known as osteopetrosis acro-osteolytica or Toulouse-Lautrec syndrome, is a rare autosomal recessive bone dysplasia, characterised by osteosclerosis and short stature.
Pyknodysostosis is a lysosomal disorder due to genetic deficiency in Cathepsin K which has bee...
Hypertrophic pyloric stenosis (HPS) refers to the idiopathic thickening of gastric pyloric musculature which then results in progressive gastric outlet obstruction.
Pyloric stenosis is relatively common and has a male predilection (M:F ~4:1), and is more commonly seen in Caucasia...
Rachipagus twins are extremely rare type of conjoined twins. They are joined in the dorsal aspect and face away from each other.
Fusion of the occiput with varying segments of the vertebral column may occur, resulting in the sharing of the spinal cords. The fusion terminates above the sacrum. F...
Rachitic rosary refers to expansion of the anterior rib ends at the costochondral junctions and is most frequently seen in rickets as nodularity at the costochondral junctions.
Other causes of this appearance include:
the costochondral junction is more angula...
Radial head dislocation occurs when the radial head is displaced from its normal articulation with the ulna and the humerus.
The dislocation may be acquired or congenital (see the separate article on congenital radial head dislocation). Additionally, radial head dislocation should be distinguis...
Radial ray anomalies comprise of a large spectrum of upper limb anomalies which range from partial (radial hypoplasia) to a complete (radial aplasia) deficiency of the radius with or without accompanying deficiency of the thumb bones.
They can be associated with a numbe...
The radiocapitellar line is one of the key lines used to assess alignment on the elbow radiograph. It is particularly useful in the paediatric setting.
A line drawn down the neck of the radius should intersect the capitellum. It is important to ensure that you draw the line down the r...
Raghib syndrome is a rare developmental complex, which consists of
persistence of the left superior vena cava along with
coronary sinus ostial atresia and
atrial septal defect.
It has also been associated with other congenital malformations including ventricular septal defects, enlargement o...
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...
The rectosigmoid ratio is a measurement of the diameter of the rectum divided by that of the sigmoid colon during contrast enema. It is of particular use in the diagnosis of Hirschsprung disease.
Normal children have a rectum that is larger than the sigmoid (i.e. rectosigmoid ration >1). In fac...
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 tumours (for the purposes of this article taken to broadly mean neoplastic lesions) should be distinguished from renal pseudotumours.
Whilst renal tumours can be broadly divided into primary and secondary (metastatic), benign and malignant or adult and paediatric tumours, they are more fo...
Respiratory distress syndrome (RDS) is a relatively common condition resulting from insufficient production of surfactant that occurs in preterm neonates.
On imaging, the condition generally presents as bilateral and relatively symmetric diffuse ground glass lungs with low volumes and a bell-s...
Retinoblastomas are the most common intraocular neoplasm found in childhood, and with modern treatment modalities are, in most cases, curable.
On imaging, they are generally characterised by a heterogeneous retinal mass with calcifications, necrotic components, and increased vascularisation on ...
Retinopathy of prematurity (ROP) (formerly referred to as retrolental fibroplasia) is an ocular condition seen in the infant population. It often occurs bilaterally, although usually with significant asymmetry 1.
There is often a history of premature delivery, low birth weight, a...
Rhabdoid tumour of the kidney is a rare, highly aggressive malignancy of early childhood, closely related to atypical teratoid/rhabdoid tumours (AT/RT) of the brain (see rhabdoid tumours)
Rhabdoid tumours occur exclusively in children, with 60% occurring before the age of 1 year o...
Rhabdoid tumours are rare and extremely aggressive tumours of early childhood. They occur in a number of locations:
kidney: see malignant rhabdoid tumour of the kidney, most common
intracranial: see atypical teratoid/rhabdoid tumour (AT/RT)
soft tissues, including:
Rhabdomyosarcoma is a malignant tumour with skeletal muscle cell morphology. It is one of the tumours of muscular origin.
This article focuses on a general discussion of rhabdomyosarcomas. For location specific details, please refer to:
rhabdomyosarcomas of the biliary tract
Rhabdomyosarcomas of the genitourinary tract are uncommon tumours occurring in pelvic organs. It is a disease nearly exclusive to the paediatric population.
For a general discussion of this type of tumour, please refer to the article on rhabdomyosarcomas.
The peak incidence of ...
Rhabdomyosarcomas of the orbit account for approximately 10-20% of all rhabdomyosarcomas and are usually found in children.
As with other locations, rhabdomyosarcomas in the orbit are overrepresented in males, and in Caucasians. They typically occur in children below the age of 1...
Rhabdomyosarcomas of the biliary tract are rare tumours, usually identified in children, with a very poor prognosis. They are usually grouped under botryoid rhabdomyosarcomas.
For a general discussion of this type of tumour, please refer to the article on rhabdomyosarcomas.
Rhabdomyosarcomas of the head and neck represent a large proportion (~40%) of all rhabdomyosarcomas. For a general discussion of this tumour, please refer to rhabdomyosarcoma.
There are usually of the embryonal in cell subtype and are essentially only seen in children. They are classified by lo...
Rhombencephalosynapsis (RS) is a congenital abnormality of the cerebellum characterised by the vermis absence and continuity of the cerebellar hemispheres, dentate nuclei, and superior cerebellar peduncles. It either occurs as an isolated anomaly (rare) or as part of wider cerebral malformation ...
Rickets, less commonly known as rachitis, essentially refers to osteomalacia in the paediatric population that occurs before fusion of the growth plate.
Rickets is seen in a number of distinct populations which include 4:
premature infants (especially if on parenteral nutrition)
Right middle lobe syndrome refers to chronic right middle lobe collapse, without an obstructing lesion, and usually with associated bronchiectasis.
Right middle lobe syndrome is usually encountered in older adults, with a predilection for women (see Lady Windermere syndrome). It ...
Ritscher-Schinzel syndrome (RTSC), also known as 3C (cranio-cerebello-cardiac) syndrome, is a rare entity with a variable spectrum of CNS (primarily cerebellar), craniofacial, and congenital heart defects.
Roberts Syndrome (RBS) (also known as Roberts-SC phocomelia syndrome, pseudothalidomide syndrome, Appelt-Gerken-Lenz syndrome) is rare congenital malformation syndrome. It has an autosomal recessive inheritance.
intrauterine growth restriction (IUGR)
Robin sequence (also called Pierre Robin syndrome or Pierre Robin anamaloid) is a congenital condition characterized by facial abnormalities. Its aetiology has no genetic base, but rather, is reliant on a sequence of events, one following the other.
Robin sequence is the preferred ...
Round pneumonia is a type of pneumonia usually only seen in paediatric patients. They are well defined, rounded opacities that represent regions of infected consolidation.
The mean age of patients with round pneumonia is 5 years and 90% of patients who present with round pneumonia...
Sacral agenesis (also considered as part of the caudal regression syndrome) is a rare and severe sacral developmental abnormality.
In normal pregnancy, the incidence is between 0.005 and 0.1%. However, in fetuses with diabetic mothers, the incidence rises to 0.2%. Of those with th...
Sacral dimples are a clinical and radiological feature that is associated with occult spinal dysraphism (e.g. tethered cord syndrome) but are more frequently a non-significant isolated finding.
Common in healthy children (~5%) 1.
Simple sacral dimples have the followin...
Sacrococcygeal teratoma (SCT) refers to a teratoma arising in the sacrococcygeal region. The coccyx is almost always involved 6.
It is the commonest congenital tumour in the fetus 11 and neonate 3. The incidence is estimated at ~1:35000-40000. There is recognised female predilecti...
The Sakati-Nyhan syndrome, also known as Sakati-Nyhan-Tisdale syndrome or acrocephalosyndactly type III, is an extremely rare type of acrocephalopolysyndactyly.
Its main features include:
congenital limb abnormalities
congenital heart defects
History and etymology
The Salter-Harris classification was proposed by Salter and Harris in 1963 1 and at the time of writing (June 2016) remains the most widely used system for describing physeal fractures.
Conveniently the Salter-Harris types can be remembered by the mnemonic SALTR.