Lithopaedions, also referred as stone babies, are a rare phenomenon which occurs most commonly when a fetus dies during an ectopic pregnancy.
The estimated incidence is at ~ 1.5 to 1.8% of abdominal ectopic pregnancies 4.
If the deceased fetus is too large to be re-abs...
Paediatric liver lesions are a heterogeneous group that include infiltrative lesions and those that demonstrate mass effect. Moreover, they may be solitary or multiple, benign or malignant:
benign liver tumours
malignant liver tumours
There are differing frequencies of both beni...
Lobar holoprosencephaly is the least severe of the classical subtypes of holoprosencephaly (HPE), characterised by the presence of the inter-hemispheric fissure along almost the entire midline, and with the thalami being completely or nearly completely separated 5.
As with all types of HPE, it ...
Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder which has many features similar to Marfan syndrome.
The disease is characterised by skeletal manifestations and vasculopathies. Although Loeys-Dietz syndrome shares many similarities with Marfan syndrome, the course ...
Luckenschadel skull, also known as lacunar skull or craniolacunae, is a dysplasia of the membranous skull vault and is associated with Chiari II malformations (seen in up to 80% of such cases). The inner table is more affected than the outer, with regions of apparent thinning (corresponding to n...
Lumbar Scheuermann disease is a type of variant Scheuermann disease where there are some radiological features of Scheuermann's disease without an abnormal kyphosis.
On radiographs, affected individuals can have vertebral end plate changes, disc space narrowing, and anterior Schmorl's nodes, bu...
Lymphangiomas are benign lesions of vascular origin that show lymphatic differentiation. It is considered the lymphatic equivalent of a haemangioma of blood vessels.
This article focuses the general features of lymphangiomas. For a specific discussion in other locations, please refer to the ar...
Lytic skull lesions have a relatively wide differential that can be narrowed, by considering if there are more than one lesion and whether the mandible is involved.
lytic skeletal metastases
epidermoid - scalloped border with a sclerotic rim
Macrodystrophia lipomatosa is a rare form of localised gigantism, and many terms have been used interchangeably, with resulting confusion. They include macrodactyly, megalodactyly, digital gigantism, macromelia, partial acromegaly, macrosomia, and limited gigantism 3.
It is worth noting that m...
Macroglossia means an enlarged tongue. It may be absolute (greater than the 95th centile) or relative (enlarged compared with oral cavity).
Recognised associations include:
tends to be a relative macroglossia
may also have intermi...
Madelung deformity is due to premature closure or defective development of the ulnar third of the distal epiphysis of the radius. This deformity results in a radial shaft that is bowed with increased interosseous space and dorsal subluxation of the distal radioulnar joint.
It can be bilateral ...
Major aortopulmonary collateral arteries (MAPCAs) are persistent tortuous fetal arteries that arise from the descending aorta and supply blood to pulmonary arteries in the lungs usually at the posterior aspect of hilum.
Embryologically, the intersegmental arteries regress with the no...
Paediatric malignant liver tumours are rare, some of which occur only in children but that are similar to those that occur in adults.
Malignant liver tumours account for ~1% of paediatric malignancies 2.
Broadly, any malignant liver mass can be defined as a metastasis ...
Maple syrup urine disease (MSUD) is a very rare metabolic disorder. It is an inborn error of amino acid metabolism, which classically affects the brain tissue resulting in impairment or death if untreated.
MSUD occurs in 1 in 185,000 births 9.
It usually ma...
Marshall-Smith syndrome (MSS) is a rare genetic syndrome primarily comprising of the triad of facial dysmorphism, failure to thrive and accelerated osseous maturation 5. Many cases however have wider clinical spectrum.
overgrowth - fetal macrosomia
failure to thriv...
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterised by
hydrometrocolpos - vaginal atresia
congenital heart disease
Measles is a highly contagious infection caused by the measles virus.
The measles vaccine, first introduced in 1963, has significantly reduced the incidences of measles. However, it remains endemic in countries with low vaccination rates 1. Worldwide, it is the leading cause of va...
Meckel diverticulum is a congenital intestinal diverticulum due to fibrous degeneration of the umbilical end of the omphalomesenteric (vitelline) duct that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract.
Meckel-Gruber syndrome (MGS) is classically characterised by the triad of:
renal cystic dysplasia: multiple renal cysts (present most cases)
occipital encephalocoele / holoprosencephaly (~70%)
postaxial polydactyly: usually hexadactyly (~65%)
Additional hepatic developmental defects and hepa...
Meconium aspiration occurs secondary to intrapartum or intrauterine aspiration of meconium, usually in the setting of fetal distress, and usually in term or post-term infants.
Up to 10-15% of live births after 34 weeks can present with meconium stained fluid but only 1-5% of neona...
Meconium ileus refers to a neonatal bowel obstruction of the distal ileum due to abnormally thick and impacted meconium. Unlike in the meconium plug syndrome, the meconium is abnormal in consistency.
Meconium ileus is more common in white populations and affects both sexes almost ...
Meconium peritonitis refers to a sterile chemical peritonitis due to intra-uterine bowel perforation and spillage of fetal meconium into the fetal peritoneal cavity. It is a common cause of peritoneal calcification.
The estimated prevalence is at ~1 in 35,000.
Meconium plug syndrome refers to a functional colonic obstruction in a newborn due to an obstructing meconium plug. It is usually transient and affects the left colon with meconium plugging the bowel distal to this segment. In this situation, it is also termed the small left colon syndrome.
Meconium pseudocyst formation is a complication that can occur with meconium peritonitis.
It occurs when the extruded meconium becomes walled off within the peritoneal space.
May be seen as a rim calcified mass within the abdomen.
Medial epicondyle fractures represent almost all epicondyle fractures and occur when there is avulsion of the medial epicondyle. They are typically seen in children, and can be challenging to identify. Failure to diagnose these injuries can lead to significant long term disability.
Medial pneumothorax refers to the abnormal collection of air on medial aspect of the pleural cavity. This occurs when the quantity of air is small.
Chest radiograph (supine)
Seen as a linear lucent area along the medial aspect of lung at the interface of the pleural surf...
Medial stripe sign refers to an area of increased lucency at the interface of the medial lung and the mediastinum in case of medial pneumothorax. A small volume of pneumothorax generally accumulates anteriorly or medially which can be difficult to detect hence this sign holds a certain significa...
Medullary cystic disease complex belongs to group of paediatric cystic renal diseases charaterised by progressive tubular atrophy with glomerulosclerosis (chronic tubulointerstitial nephritis) and multiple small medullary cysts.
There is no recognised gender predilection
Medulloblastomas are the most common malignant brain tumour of childhood. They most commonly present as midline masses in the roof of the 4th ventricle with associated mass effect and hydrocephalus. Treatment typically consists of surgical resection, radiation therapy, and chemotherapy, with the...
Megalencephalic leukoencephalopathy with subcortical cysts, also known as Van der Knaap disease, refers to a rare inherited autosomal recessive disease characterised by diffuse subcortical leukoencephalopathy associated with white matter cystic degeneration.
The age at symptoms m...
Megalencephaly-capillary malformation (MCAP) syndrome, also known as macrocephaly-capillary malformation syndrome, is a rare and well described genetic disorder caused by somatic mutations in the PIK3CA gene on chromosome 3q26 and characterised by early brain overgrowth and body morphogenesis an...
Melanotic neuroectodermal tumour of infancy (MNTI) is a rare pigmented tumour that primarily affects the calvaria or facial skeleton of children, typically during infancy. It is usually a benign tumour, albeit locally aggressive.
Most cases are diagnosed during infancy, usually wi...
The mendosal suture (also known as the accessory occipital suture) is a normal calvarial suture.
The suture extends through the occipital bone, lying superior to the occipitomastoid suture and inferomedial to the lambdoid suture. It closes in utero or in the first few days of lif...
Meningoceles are protrusions of the meninges through a defect or weak point in the skull or spine, usually involving the soft tissues beneath the surface of the skin. They are typically categorized into congenital, iatrogenic (e.g. following a craniotomy, sinus surgery, or as a laminectomy compl...
Menkes disease, also known as trichopoliodystrophy or Kinky hair kinky vessel syndrome, is an X-linked recessive disorder that results in a derangement in copper handling. It results in low copper levels and subsequently, deficiency in copper dependant mitochondrial enzymes.
MERRF (myoclonic epilepsy with red ragged fibres) is a rare, multisystem mitochondrial disorder.
Patients usually present in late adolescence or early adulthood with 1,2,3
vision and/or hearing loss
A mesenchymal hamartoma of the chest wall is a very rare benign chest wall tumour. It is sometimes classified as a non-neoplastic developmental anomaly rather than a tumour.
They typically present in neonates or infants 1-3.
Many present with a chest wall m...
Mesomelia refers to a shortening of the middle (intermediate) portion of a limb.
mesomelia-synostoses syndrome (MSS) or mesomelic dysplasia with acral synostoses1
Ellis van-Creveld syndrome 2
Metachondromatosis refers to the rare combination of:
multiple enchondromatosis (Ollier disease) and
osteochondromatosis (diaphyseal aclasis)
In contrast to enchondromatosis alone, metachondromatosis carries an autosomal dominant inheritance.
Characterised by the pre...
Metachromatic leukodystrophy (MLD) is the most common hereditary (autosomal recessive) leukodystrophy and is one of the lysosomal storage disorders. It has characteristic imaging features including peri-atrial and to a lesser extent frontal horns leukodystrophy as well as periventricular periven...
The metaphyseal blanch sign (a.k.a. metaphyseal blanch sign of Steel) is one of the signs seen on AP views of the adolescent hip indicating posterior displacement of the capital epiphysis.
It is a crescent-shaped area of increased density, that overlies the metaphysis adjacent to the physis on ...
Metaphyseal corner fractures, also known as classical metaphyseal lesions (CML) or bucket handle fractures, are observed in young children, less than 2 years old. It is considered pathognomic for non-accidental injury (NAI).
This injury is not only the fracture most specific for ...
Metaphyseal dysplasia (also known as Pyle disease) is a rare autosomal recessive disorder characterised by flaring of the ends of long bones with relative constriction and sclerosis of the diaphysis and mild cranial sclerosis. It is one of the causes of an Erlenmeyer flask deformity. The flared ...
Meyer dysplasia (also known as dysplasia epiphysealis capitis femoris) is a fragmentation and delayed ossification of the femoral capital epiphyses that affects the paediatric hips. It is considered more of a normal hip developmental variation rather than a true dysplasia. It can be bilateral in...
MIBG scan is a scintigraphic study that uses metaiodobenzylguanidine labeled to iodine-123 or iodine-131. It is indicated in the investigation of phaeochromocytoma.
MIBG is positive in:
olfactory neuroblastoma 1
carcinoid tumour 4
Microcephaly is a descriptive term meaning a small head and is associated with numerous disorders of diverse aetiology. It is usually associated with microencephaly (small brain). For the purpose of this article the two will be used interchangeably.
As with most terms which describ...
Midface anomalies (craniofacial syndromes ) in children include
Treacher Collins syndrome
Midgut volvulus is a complication of malrotated bowel and results in a proximal bowel obstruction and ischaemia.
A midgut volvulus of malrotated bowel can potentially occur at any age but in approximately 75% of cases is within a month of birth 4,6, most within the first week 3, a...
Miller-Dieker syndrome (MDS) or is a rare chromosomal anomaly and is one of the conditions considered part of lissencephaly type I (classic) 6.
neuronal migrational anomalies: lissencephaly type I
prominent subarachnoid spaces
widened cerebral v...
Mineralising microangiopathy is a condition characterized by parenchymal cerebral calcifications, and is usually seen in children as a complication of cranial radiotherapy and chemotherapy 1,2.
Mineralizing microangiopathy can affect the brain widely, with typical sites i...
M-line of Cremin is an imaginary line that can be used to determine the level at which the blind pouch ends in anal atresia, determining whether the anal atresia is a high or a low type.
The line is drawn perpendicular to the long axis of the ischium on the lateral view and passes through the j...
Möbius syndrome, also known as congenital facial diplegia syndrome, is a rare congenital condition characterised by the absence or underdevelopment of the abducens nerve (CN VI) and facial nerve (CN VII) nuclei.
Möbius syndrome is rare with an estimated incidence of ~1 case per 10...
Monteggia fracture-dislocations consist of a fracture of the ulnar shaft with concomitant dislocation of the radial head. The ulnar fracture is usually obvious, whereas the radial head dislocation can be overlooked, with potentially serious functional and medico-legal ramifications.
Morquio syndrome is an autosomal recessive mucopolysaccharidosis (MPS), type IV.
Incidence estimated at ~1:40,000.
Many cases present at ~2 years of age and have normal intelligence. Clinical features:
severe dwarfism (<4 foot)
Moyamoya disease is an idiopathic, non inflammatory, non atherosclerotic progressive vasculo-occlusive disease involving the circle of Willis, typically the supraclinoid internal carotid arteries.
The term moyamoya disease should be reserved for an idiopathic, sometimes familial, ...
Mucopolysaccharidoses (MPS) constitute a group of hereditary disorders, one of a number of lysosomal storage disorders, having in common an excessive accumulation of mucopolysaccharides secondary to deficiencies in specific enzymes (lysosomal hydrolases) responsible for degradation of mucopolysa...
Multicentric carpal tarsal osteolysis is a rare skeletal disorder which is characterized by progressive osteolysis of the carpal, metacarpal and tarsal bones. It usually presents in early childhood with progressive pain and stiffness of the wrist, feet and elbow, clinically mimicking juvenile rh...
Multicystic dysplastic kidney (MCDK) is a type of non-heritable paediatric cystic renal disease. It results in multiple cysts being formed in utero in the affected kidney.
Unilateral incidence is estimated at 1:2500-4000. There may be a predisposition for the left kidney, a slight...
Multicystic encephalomalacia (MCE) corresponds to a variant of encephalomalacia commonly seen in neonates in which numerous loculated lacy pseudocysts within the white matter and cortex are present as a result of an extensive brain insult.
It is a common feature observed in the neonatal hypoxi...
Multilocular cystic renal tumours (MCRT) are rare benign renal neoplasms occurring in a bimodal age distribution, involving young children and adults in the 4th and 5th decades.
For logical reasons, this article will discuss together the two ends of the spectrum of this disease, cystic partiall...
Multiple synostoses syndrome (SYNS), proximal symphalangism (SYM), tarsal-carpal coalition (TCC) syndrome, stapes ankylosis with broad thumbs and toes (SABTT), and brachydactyly B2 (BDB2) are overlapping autosomal dominant conditions united by typically displaying ankylosis of the proximal inter...
The mushroom sign (also called umbrella sign) is a radiological sign described in pyloric stenosis on barium examination.
This sign refers to the impression made by the hypertrophic pylorus on the duodenal cap.
cervix sign of pyloric stenosis
target sign of pyloric st...
The Mustard repair is a technique to correct transposition of the great arteries (TGA), and involves:
resection of atrial septum
creation of an atrial baffle with pericardium (or rarely synthetic material) 1
Transposition of the great arteries involves a discordance between the ven...
Nasal encephaloceles are in most cases a form of neural tube defect particularly common in Southeast Asia. They are are herniation of cranial content through a bony defect in the anterior skull base into the nasal area.
The term is variably used but generally encompasses both frontoethmoidal en...
Nasal gliomas, also know as nasal glial heterotopia, are a rare congenital lesion composed of dysplastic glial cells which have lost their intracranial connections and present as an extranasal or intranasal mass.
Nasal gliomas are rare congenital lesions. These masses occur spora...
Necrotising enterocolitis (NEC) is the most common gastrointestinal condition in premature neonates. It is characterised by inflammation, ischaemia, and permeability of the neonatal bowel wall to bacteria. It is potentially life-threatening with significant associated morbidity.
Necrotising enterocolitis (NEC) can be staged into three groups, helping to guide appropriate treatment. In general, stage I and II are managed medically whereas stage III is managed surgically.
lethargy, temperature instability, apnoea, bradycardia
emesis, abdominal d...
Necrotising pneumonia refers to pneumonia characterised by the development of the necrosis within infected lung tissue.
While the term has sometimes been used synonymously with cavitating pneumonia in some publications 2, not all necrotising pulmonary infections may be complicated ...
Neonatal appendicitis is rare, presumably in part due to the short funnel shape to the appendix at that age. Symptoms are non-specific and may mimic necrotising enterocolitis.
Neonatal bilious vomiting has a relatively narrow differential - those conditions that cause intestinal obstruction, but do so distal to the ampulla of Vater. As such, the list includes:
malrotation with midgut volvulus
The neonatal chest radiograph in the exam setting may strike fear into the heart of many radiology registrars, but it need not!
There are only a limited number of diagnoses that will be presented on such films and they are often highlighted by the history.
First of all, have a look ...
Neonatal encephalopathy is a clinical syndrome referring to signs and symptoms of abnormal neurological function in the first few days of life in a neonate born at or beyond 35 weeks of gestation. It is described as difficulty with initiating and maintaining respiration, depression of tone and r...
Neonatal herpes simplex encephalitis is caused by vertical transmission of infection during passage from birth canal with diffuse cerebral involvement within the first month after birth; in contrast to adult herpes simplex encephalitis, it is commonly related to HSV-2.
Neonatal hydronephrosis is most commonly diagnosed antenatally as fetal pylectasis, and in the majority of cases is due to pelvi-ureteric junction (PUJ) obstruction.
pelvi-ureteric junction (PUJ) obstruction (50% of cases 1,6)
vesicoureteric reflux (~20% of cases 5)
Neonatal hypoxic-ischaemic encephalopathy (HIE) is the result of a global hypoxic-ischaemic brain injury in a term neonate, usually after asphyxia.
It is important to remember that neonatal encephalopathy may result from a variety of conditions and hypoxic-ischaemic brain injury is...
Neonatal lines and tubes are widely used in the NICU (neonatal intensive care unit) in the management of critically ill neonates. Examples include:
nasogastric (NG) tube
endotracheal (ET) tube
central venous line
umbilical artery catheter
umbilical vein catheter
The NG tu...
Neonatal neuroblastoma is a type of congenital neuroblastoma, an embryonal tumour arising from the sympathetic nervous system. In the majority of cases (45%), the tumour is localised in the adrenal gland.
Neonatal neuroblastoma accounts for less than 5% of all cases and carrie...
Neonatal pneumonia refers to inflammatory changes of the respiratory system caused by neonatal infection.
It is one of the leading causes of significant morbidity and mortality in developing countries. Neonatal pneumonia accounts for 10% of global child mortality. At the time of w...
The causes of neonatal pneumoperitoneum are different from adult pneumoperitoneum and include:
perforated hollow viscus
necrotising enterocolitis (NEC): most common
meconium ileus in cystic fibrosis
intestinal atresia or web
peptic ulcer disease
Neonatal pneumothorax describes pneumothoraces occurring in neonates. It is a life threatening condition, associated with high morbidity and mortality. The diagnosis is a challenge especially when the amount of air is small and may accumulate along the anterior or medial pleural space.
Causes of neonatal distress can be broadly split into intrathoracic, extrathoracic and systemic:
respiratory distress syndrome (RDS)
transient tachypnoea of the newborn (TTN)
meconium aspiration syndrome
bronchopulmonary dysplasia (BPD)
patent ductus arteriosus (PDA)...
Nephroblastomatosis refers to diffuse or multifocal involvement of the kidneys with nephrogenic rests (persistent metanephric blastema).
Nephrogenic rest are found incidentally in 1% of infants.
Nephrogenic rests are foci of metanephric blastema that persist beyond 36 ...
Nephrotic syndrome (NS) results from loss of plasma proteins in the urine and characterised by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and oedema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes.
Patients present with ...
Neuhauser sign refers to a soap bubble appearance seen in the distal ileum in cases of meconium ileus, related to the air mixed with meconium. It may be seen with barium enema if contrast passes beyond the ileocaecal valve or with small-bowel follow-through.
Although classically described with ...
The neurenteric canal or canal of Kovalevsky is the transient communication of the amnion through notochordal canal to the yolk sac during notochordal formation at day 16-17.
Abnormalities during this stage produce the neurenteric cyst spectrum.
Neuroblastic tumours arise from primitive cells of the sympathetic system and include the following entities:
These entities represent a spectrum of disease from undifferentiated and aggressive (neuroblastoma) to the well differentiated and l...
Neuroblastomas are tumours of neuroblastic origin. Although they may occur anywhere along the sympathetic chain, the vast majority arise from the adrenal gland.
They represent the most common extracranial solid childhood malignancy and are the third commonest childhood tumour after leukaemia an...
There are two methods of neuroblastoma staging, one that is based on post-operative patients (INSS) and one developed for pre-treatment patients (INRGSS).
International Neuroblastoma Staging System (INSS)
This staging system is for post-operative patients and mainly for prognosis 1:
Both neuroblastoma and Wilms tumour occur in early childhood and typically present as large abdominal masses closely related to the kidneys. Distinguishing between the two is important, and a number of features are helpful.
calcification very common: 90%
encases vascular structu...
Neurocristopathy syndromes encompasses a group of conditions united by abnormal migration, differentiation, division or survival of neural crest cells 1.
neurofibromatosis type I (NF1)
Neurofibromas are benign peripheral nerve sheath tumours usually solitary and sporadic, however, there is a strong association with neurofibromatosis type 1 (NF1). These tumours present as a well-defined hypodense mass with minimal or no contrast enhancement on CT. On MRI, they usually are T1 hy...
Niemann-Pick disease (NPD) is actually a collection of a number of distinct autosomal recessive lysosomal storage diseases.
deficiency of acid sphingomyelinase 1
Niemann-Pick disease type A (NPA)
severe hepatosplenomegaly in infancy
severe central nervous system involvement, with atrophy or...
Niemann-Pick type B disease (NPD-B), along with Niemann-Pick type A (NPD-A) disease, is one of the more common forms of this group of autosomal recessive disorders that share the feature of abnormal storage of sphingomyelin. Common manifestation includes splenomegaly and variable neurologic defi...