Macrodystrophia lipomatosa is a rare form of localized 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 ma...
Macroglossia means an enlarged tongue. It may be absolute (greater than the 95th centile) or relative (enlarged compared with oral cavity).
Recognized associations include:
tends to be a relative macroglossia
may also have intermi...
Madelung deformity refers to bowing of the radial shaft with increased interosseous space and dorsal subluxation of the distal radioulnar joint. This deformity is due to premature closure or defective development of the ulnar third of the distal epiphysis of the radius.
Madelung deformity can b...
Mainzer-Saldino syndrome (also known as conorenal syndrome (CRS)) is a rare condition and is one of the ciliopathies. It is due to mutations in the IFT140 gene, whose protein product is one of the six parts of the intraflagellar transport complex A.
The syndrome's key characteristics are:
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...
Pediatric malignant liver tumors are rare, some of which occur only in children but that are similar to those that occur in adults.
Malignant liver tumors account for ~1% of pediatric malignancies 2.
Broadly, any malignant liver mass can be defined as a metastasis or p...
The mammalian target of rapamycin (mTOR), also known as mechanistic target of rapamycin, are two proteins that are involved in cell signaling pathways implicated in tumorigenesis.
The mTOR proteins are serine/threonine protein kinases that combine with several other proteins to form two large c...
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 the triad of facial dysmorphism, failure to thrive and accelerated osseous maturation 5. Many cases, however, have a wider clinical spectrum.
failure to thrive
The mastoid or posterolateral fontanelles are paired bilateral soft membranous gaps (fontanelles) at the junction of the parietomastoid, occipitomastoid, and lambdoid sutures. Each mastoid fontanelle persists until the second year of life, after which it is known as the asterion. It can be used ...
Mauclaire disease, also known as Dietrich disease, is a rare disease and refers to osteonecrosis of the metacarpal heads, which usually appears between ages of 13 and 18 years 1,2. This condition may lead to early closure of epiphyseal growth plate and growth disturbance of the involved finger.
Mayer-Rokitansky-Küster-Hauser syndrome (MRKH), also known as Müllerian agenesis, is a congenital anomaly characterized by vaginal agenesis associated with, in the majority of cases, a spectrum of other genitourinary tract abnormalities. MRKH syndrome belongs to class I Mullerian duct anomalies....
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterized by
hydrometrocolpos - vaginal atresia
congenital heart disease
Measles (also known as rubeola) 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...
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 characterized 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 hepati...
Meconium aspiration occurs secondary to intrapartum or intrauterine aspiration of meconium, usually in the setting of fetal distress, often 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 neonates de...
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...
The medial stripe sign refers to an area of increased lucency at the interface of the medial lung and the mediastinum on a chest radiograph in a case of medial pneumothorax. A small pneumothorax generally accumulates anteriorly or medially which may be difficult to detect, hence this sign holds ...
Medullary cystic disease complex belongs to group of pediatric cystic renal diseases characterized by progressive tubular atrophy with glomerulosclerosis (chronic tubulointerstitial nephritis) and multiple small medullary cysts.
There is no recognized gender predilection
Medulloblastomas are the most common malignant brain tumor 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 characterized 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 characterized by early brain overgrowth and body morphogenesis an...
Megalocornea is a rare bilateral congenital ocular defect characterized by a corneal diameter of more than 13 mm with the deep anterior chamber and normal intraocular pressure 1-3.
Megalcornea is associated with Chordin-like 1 (CHRDL1) gene mutation 1,2. It is associated with mult...
MEGDEL syndrome (3-MEthylGlutaconic aciduria, Deafness, Encephalopathy, Leigh-like syndrome) is a recently described syndrome with infantile onset. These patients typically initially receive a diagnosis of Leigh syndrome, based on clinical and biochemical features and an abnormal basal ganglia s...
Melanotic neuroectodermal tumor of infancy (MNTI) is a rare pigmented tumor that primarily affects the calvaria or facial skeleton of children, typically during infancy. It is usually a benign tumor, albeit locally aggressive.
Most cases are diagnosed during infancy, usually withi...
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-dependent mitochondrial enzymes.
Mercedes Benz pattern craniosynostosis also known as pure bilateral lambdoid and sagittal synostosis (BLSS) is a pattern of craniosynostosis. 1-2
The estimated incidence is at around 0.3 - 0.7 % 3.
Cognitive function is grossly normal. Dolichocephalic head...
A mesenchymal hamartoma of the chest wall is a very rare benign chest wall tumor. It is sometimes classified as a non-neoplastic developmental anomaly rather than a tumor.
They typically present in neonates or infants 1-3.
Many present with a chest wall mas...
Mesenteric adenitis (rare plural: adenitides) (less commonly called mesenteric lymphadenitis (rare plural: lymphadenitides)) is a self-limiting inflammatory process that affects the mesenteric lymph nodes in the right lower quadrant and is clinically often thought initially to be acute appendici...
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.
Characterized 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 (or 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 the ...
Metaphyseal chondrodysplasia (also known as metaphyseal dysplasia or dysostosis) is a type of skeletal dysplasia.
Schmid type - mild type, due to mutation in type X collagen (COL10A1 gene), metaphyses are cupped resembling rickets
Pena and Vaandrager type - intermedi...
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 suggestive of non-accidental injury (NAI).
This injury is not only the fracture most specific for NAI, it is al...
Metaphyseal dysplasia (also known as Pyle disease, metaphyseal chondrodysplasia, metaphyseal dysostosis) is a rare autosomal recessive disorder characterized by flaring of the ends of long bones with relative constriction and sclerosis of the diaphysis and mild cranial sclerosis. It is one of th...
Meyer dysplasia (also known as dysplasia epiphysealis capitis femoris) is a fragmentation and delayed ossification of the femoral capital epiphyses that affects the pediatric 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, norepinephrine analog, labeled to iodine-123 or iodine-131. It is indicated in the investigation of pheochromocytoma.
MIBG is positive in:
olfactory neuroblastoma 1
carcinoid tumor 4
Microcephaly (plural: microcephalies) is a descriptive term meaning a small head and is associated with numerous disorders of diverse etiology. It is usually associated with microencephaly (plural: microencephalies) (small brain). For the purpose of this article, the two will be used interchang...
Microgallbladder is a common abdominal manifestation of cystic fibrosis. It defines a gallbladder that has a length less than 2-3 cm and a width less than 0.5-1.5 cm on sonographic evaluation 1.
The incidence of microgallbladder varies considerably in the literature, however most ...
The term micrognathia describes a small mandible.
Micrognathia is associated with a vast array of other congenital anomalies which include:
trisomy 9 4
arterial tortuosity syndrome
Midaortic syndrome is an uncommon entity affecting children and young adults. It is characterized by progressive narrowing of the abdominal aorta and its major branches.
The onset of symptoms is usually during childhood or young adulthood 2:
hypertension (most common)
Midface anomalies (craniofacial syndromes ) in children include
Treacher Collins syndrome
Midgut volvulus is a complication of malrotated bowel. It may result in proximal bowel obstruction with resultant ischemia if prompt treatment is not instigated.
A midgut volvulus of malrotated bowel can potentially occur at any age but in approximately 75% of cases occur within 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. It is the form of lissencephaly that is most recognizable on prenatal imaging due to its severity 5.
Mineralizing 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 in...
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 characterized by the absence or underdevelopment of the nuclei of the abducens (CN VI) and facial nerve (CN VII).
Möbius syndrome is rare with an estimated incidence of ~1 case per 1...
Molybdenum cofactor deficiency (MCD or MOCD) is a very rare, lethal, genetic condition caused by a loss of function of molybdenum-dependent enzymes, manifesting as severe and rapid neurological deterioration. On imaging it mimics hypoxic-ischemic encephalopathy.
Less than 150 repo...
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.
Morgagni hernias (alternative plural: herniae) are one of the congenital diaphragmatic hernias (CDHs), and are characterized by herniation through the foramen of Morgagni. When compared to Bochdalek hernias, Morgagni hernias tend to be:
more often right-sided (~90%)
rare (~2% ...
Morquio syndrome (in older literature it is sometimes called Morquio-Brailsford 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. Cl...
Moyamoya disease is an idiopathic, non-inflammatory, non-atherosclerotic progressive vasculo-occlusive disease involving the terminal supraclinoid internal carotid arteries and circle of Willis.
The term moyamoya disease should be reserved for an idiopathic, sometimes familial, c...
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...
Multicentric ossification refers to normal, or variant of normal, ossification at more than one site within a single epiphysis or apophysis. It is important to be aware of common sites where multicentric ossification may occur, to avoid confusion with fracture, apophysitis and other entities.
Multicystic dysplastic kidney (MCDK) is a type of non-heritable pediatric 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 slightl...
Multicystic encephalomalacia 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 h...
The multiple pterygium syndrome (MPS) refers to a group of syndromes which are collectively characterized by multiple soft tissue webs (or pterygia) across the neck and various joints.
They can be broadly classified into two main groups
lethal multiple pterygium syndrome
non-lethal multiple p...
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...
Multisystem inflammatory syndrome in children (MIS-C) or pediatric inflammatory multisystem syndrome is an emerging pediatric disease occurring after prior SARS-CoV-2 infection and is therefore strongly associated with the ongoing COVID-19 pandemic.
MIS-C is typically de...
Muscle-eye-brain disease, a part of the spectrum of congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A3; MDDGA3), is a congenital muscular dystrophy with associated progressive eye and brain abnormalities.
There is severe intellectual di...
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.
double track sign
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 a prosthetic material usually. 1,2
Transposition of the great arteries involves a discordance between the ventricles a...
Myalgic encephalomyelitis/chronic fatigue syndrome or ME/CFS, is a complex organic disorder, characterized by profound fatigue and associated marked impairment of both physical and mental functioning. Its underlying etiology is undetermined and a curative treatment remains elusive.
Myeloid sarcomas, also called granulocytic sarcomas, chloromas, or extramedullary myeloid tumors, are rare extramedullary masses comprised of myeloid precursor cells. These tumors represent a unique presentation of acute myeloid leukemia (AML), whether in isolation to, preceding, or simultaneous...
Myoclonic epilepsy with red ragged fibers (MERRF) is a rare, multisystem mitochondrial disorder.
Patients usually present in late adolescence or early adulthood with 1-3
vision and/or hearing loss
Myofibromas are benign neoplasms of soft tissues of myofibroblastic differentiation.
'Myofibroma' is used for solitary lesions and 'myofibromatosis' for multicentric lesions.
Myofibromas can occur at any age, but most predominantly occur in infants and young childre...
N-acetylaspartate (NAA) is one of the more important compounds assessed on MR spectroscopy, and resonates at 2.0 ppm chemical shift (its concentration in healthy adults is 8-10 mM) 1. The synthesis of NAA, adenosine diphosphate-dependent, occurs in the neuronal mitochondria 2.
NAA is the acetyl...
Nail-patella syndrome (also known as Fong disease, osteo-onychodysostosis, Österreicher-Turner syndrome 10, Turner-Kieser syndrome, and Trauner-Rieger syndrome) is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities.
Nasal encephaloceles are in most cases a form of neural tube defect particularly common in Southeast Asia. There is 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 enceph...
Nasal gliomas, also known 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 spor...
Necrotizing enterocolitis (NEC) is the most common gastrointestinal condition in premature neonates. It is characterized by inflammation, ischemia, and permeability of the neonatal bowel wall to bacteria. It is potentially life-threatening with significant associated morbidity 1.
Necrotizing enterocolitis (NEC) can be staged into three groups, to guide appropriate treatment based on the work of Bell et al. 1. In general, stage I and II are managed medically whereas stage III is managed surgically.
lethargy, temperature instability, apnea, bradyc...
Necrotizing pneumonia refers to pneumonia characterized 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 necrotizing pulmonary infections may be complicated ...
AP supine radiograph for neonates is a mobile examination performed on the neonatal unit. It can be taken as a standalone projection or as part of a series including a left lateral decubitus x-ray in cases of suspected perforation.
the patient is supine, lying on their back i...
Neonatal appendicitis is rare, presumably in part due to the short funnel shape of the appendix at that age. Symptoms are non-specific and may mimic necrotizing 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-ischemic encephalopathy (HIE) is the result of a global hypoxic-ischemic 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-ischemic brain injury is th...
Neonatal mastitis is rare and refers to infection of the breast tissue occurring in a neonate.
Patients may present with unilateral breast erythema and pain sometimes with associated nipple discharge and lymphadenopathy. It usually occurs in patients under five weeks of a...
Neonatal neuroblastoma is a type of congenital neuroblastoma, an embryonal tumor arising from the sympathetic nervous system. In the majority of cases (45%), the tumor is localized in the adrenal gland.
Neonatal neuroblastoma accounts for less than 5% of all cases and carries a f...