Pudendal nerve entrapment (PNE) syndrome is a rare and under-diagnosed condition associated with chronic pain, sexual dysfunction and impaired sphincter control due to compression of the pudendal nerve.
The pudendal nerve arises from S2-S4 roots of the sacral plexus, carrying both s...
Orbital apex syndrome, also known as Jacod syndrome, is a constellation of clinical findings, presenting as a result of several potential pathologies that compress or otherwise affect structures passing through the orbital apex.
Presentation is according to the structures...
Mowat-Wilson syndrome is a rare disorder with a broad spectrum of congenital anomalies. It is caused by an abnormality in the ZFHX1B gene. Anomalies that may be recognized at birth or 1st year of life include:
distinct facial profile
PIK3CA-related overgrowth spectrum (PROS) is a broad group of segmental overgrowth disorders that can occur with or without associated vascular anomalies, caused by activating mutations in the PIK3CA gene, which are also responsible for the vast majority of isolated lymphatic malformations and s...
Reye syndrome is a rare pediatric condition characterized by acute onset encephalopathy, severe vomiting and fatty liver failure. It typically presents in children recovering from a viral illness, most commonly influenza or chickenpox 1.
Reye syndrome is usually seen between the ...
Achard-Thiers syndrome is a rare condition in elderly postmenopausal females, which is illustrated by androgen excess and insulin resistance secondary to type 2 diabetes mellitus.
hirsutism in older females
high serum glucose levels
Cachexia is a syndrome of metabolic dysfunction secondary to an underlying disease in which there is depleted skeletal muscle (sarcopenia) which may or may not be accompanied by an absolute loss of body fat.
Cancer cachexia is specifically used to refer to the cachexia associated ...
Ablepharon macrostomia syndrome is a very rare genetic disorder characterized by macrostomia, wide mouth and microblepharon.
A few of the clinical features of this syndrome are:
Parkes Weber syndrome is a rare disease, depicted by capillary malformation, venous malformation, arteriovenous malformation and lymphatic malformation in the affected limb, hypertrophy of the bone, as well as soft tissues of the involved limb. Multiple AV malformation of the affected limb will...
Long COVID-19, also known as post-acute sequelae of SARS-CoV-2 infection (PASC) or post COVID-19 condition, is a post-viral syndrome affecting people who have recovered from COVID-19 infection. Symptoms are similar to those experienced by patients with chronic inflammatory response syndrome (CIR...
Auriculocondylar syndrome is a rare congenital syndrome primarily characterized by malformed ears and mandibular condyle aplasia/hypoplasia.
This is an autosomal dominant genetic disease resulting from GNAI3 or PLCB4 gene defects. This affects facial development especially the 1st an...
Gunal-Seber-Basaran syndrome is an exceedingly rare presentation of multiple bone islands, i.e. osteopoikilosis. It is characterized by dacryocystitis due to lacrimal canal stenosis with osteopoikilosis 1-3. This syndrome has an autosomal dominant inheritance 2,3.
History and etymology
Elsberg syndrome is an established but rarely recognized cause of cauda equina syndrome and lower thoracic myelitis, associated with a presumed infectious etiology.
Elsberg syndrome is likely responsible for 10% of combined cauda equina syndrome and myelitis 1.
Omodysplasia is an extremely rare short-limb skeletal dysplasia characterized by 1:
depressed nasal bridge
short Humerus with hypoplastic distal humeri
Hip spine syndrome is one term used to describe the clinical association between hip osteoarthritis and degenerative lumbar spinal canal stenosis due to overlapping pain distribution.
Patients with hip spine syndrome have hip and lumbar spine degeneration and present wit...
The post cardiac arrest syndrome (PCAS) describes the clinicopathological state that manifests following most cardiac arrests. Clinically, it is manifested by a combination of neurological disturbance, multiorgan dysfunction and a systemic inflammatory response syndrome-like state.
Godtfredsen syndrome is a rare syndrome of abducens and hypoglossal nerve palsies that localizes to a clival mass.
The classic clinical presentation includes 1-3:
abducens nerve palsy: diplopia worse when horizontal gaze is directed towards the affected side
Prefemoral fat pad impingement syndrome, also known as supratrochlear / posterior suprapatellar fat pad impingement syndrome, is one of the fat pad impingement syndromes of the knee, specifically involving the prefemoral fat pad.
Patients present with anterior knee pain e...
Neurogenic thoracic outlet syndrome is the most common cause of thoracic outlet syndrome accounting for approximately 90% of cases. It is caused by compression of the brachial plexus as it passes between the scalenus muscles, over the first rib and posteroinferior to the clavicle before entering...
McCleery syndrome is a subtype of venous thoracic outlet syndrome with symptoms resulting from compression of the subclavian vein without thrombosis (in contrast to Paget-Schroetter syndrome).
Patients with McCleery syndrome present with intermittent obstruction of the s...
Snapping scapula syndrome is an uncommon condition where on scapular movement there is pain associated with an audible or palpable grinding, clicking or snapping.
Causes include 1,2:
scapular stabilizer muscular atrophy/fibrosis, e.g. long thoracic nerve i...
Post-polypectomy coagulation syndrome occurs during a colonoscopic polypectomy procedure when electrocoagulation injury causes a transmural burn to the colon without radiographic evidence of perforation 1,2.
Post-polypectomy coagulation syndrome is also known as post-polypectomy ...
Fuhrmann syndrome is a rare non-lethal genetic limb malformation syndrome characterized by 1,2:
hypoplasia of pelvis
bowing of femur bone
symmetrical fingernail deficiency 4
tooth anomalies 5
malformed thumbs 8
It is a syndrome in which there is a partial l...
Arterial tortuosity syndrome (ATS) is a very rare autosomal recessive connective tissue disease. It is similar to Ehlers-Danlos syndrome (EDS), the major differentiator being the general tortuous nature of the larger arteries.
It presents similarly to other collagen disor...
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...
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 hea...
Multisystem inflammatory syndrome in children (MIS-C) or pediatric inflammatory multisystem syndrome (PIMS) is an emerging pediatric disease occurring after prior SARS-CoV-2 infection and is therefore strongly associated with the ongoing COVID-19 pandemic.
The World Health Organiz...
Catel-Manzke syndrome is a digitopalatal syndrome initially described in 1961. Inheritance pattern is unknown. Radiographic findings include micronagthia and accessory ossicles at the bases of the metacarpals.
Short lasting unilateral neuralgiform headache attacks can present with either conjunctival injection and tearing (SUNCT) or with cranial autonomic symptoms (SUNA) are rare headache syndromes that belong to a larger group of headaches known as trigeminal autonomic cephalgia and can present very ...
Juvenile hyaline fibromatosis, also known as hyaline fibromatosis syndrome or infantile systemic hyalinosis is a rare autosomal recessive syndrome outlined by painful, abnormal, often deforming deposits of hyalinized fibrous material in the extracellular matrix of the skin, subcutaneous soft tis...
Tapia syndrome , also called matador's disease, is a rare syndrome that is characterized by unilateral paralysis of the tongue and vocal cords. Although the problem typically occurs after anesthetic airway management or manipulation, it can be due to central causes in rare cases 11. The syndrom...
Simpson-Golabi-Behmel syndrome is a rare X-linked recessive disorder of pre- and postnatal overgrowth syndrome represented by mild to severe intellectual disability 3,7, anomalies of the musculoskeletal system, cardiovascular system, central nervous system, renal and gastrointestinal tract were ...
Perlman syndrome is a rare autosomal recessive overgrowth syndrome with earlier neonatal mortality. Maximum survival documented in the literature is up to nine years 4.
Perlman syndrome is demonstrated by a combination of many clinical features which includes polyhydramni...
Legius syndrome is a neurocutaneous disease, one of the RASopathies, and is characterized by multiple café-au-lait spots, with or without freckles and macrocephaly.
More than 200 cases were reported between 2007 and 2013 1,3.
Although rare, it is estimated that up to 2% of patien...
Riley-Day syndrome, also known as familial dysautonomia, is a rare neurodevelopmental genetic autosomal recessive disorder that primarily affects the autonomic nervous system 1,9.
Familial dysautonomia is more common in Ashkenazi Jews 1.
Posterior nutcracker syndrome is a rare vascular compression disorder, in which a retroaortic left renal vein is trapped between the aorta and the vertebral column.
The most reported clinical manifestation is microscopic or macroscopic hematuria.
Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome is a recently described constellation of imaging findings in adults with opioid neurotoxicity. It is characterized by cytotoxic edema in the bilateral hippocampi and cerebellar cortices, and va...
Pediatric opioid use‐associated neurotoxicity with cerebellar edema (POUNCE) syndrome is a toxic encephalopathy in children with opioid overdose that features prominent cerebellar edema. Cerebellar predominance, along with variable supratentorial involvement, appears to be a distinct pattern of ...
Reversible acute cerebellar toxicity (REACT) syndrome is a potentially reversible acute encephalopathic syndrome 1,2.
REACT is a rare syndrome that has been associated with several opioid and chemotherapeutic agents, including Minnelide 1,2.
The Van Wyk Grumbach syndrome is characterized by chronic hypothyroidism with high levels of thyroid-stimulating hormone (TSH), delayed bone age, precocious puberty but lacking pubic and axillary hair growth 1.
The acquired form of hypothyroidism is seen in children caused by chr...
Delirium (also known as acute brain failure) is an acute syndrome characterized by impaired intellect, awareness and concentration. Typically, the cognitive impairment fluctuates throughout the day. In contrast to dementia, delirium tends to be reversible.
The number of synonyms fo...
Spinoglenoid notch syndrome is caused by compression of suprascapular nerve due to a ganglion cyst at the spinoglenoid notch resulting in shoulder pain and posterior shoulder tenderness.
On clinical examination, there is posterior shoulder tenderness, discomfort in extern...
Keutel syndrome is an extremely rare inherited condition.
It is characterized by:
cartilage calcification of:
trachea - with resultant tracheobronchial stenosis
pulmonary arterial stenoses
brachytelephalangism (short fingers and nails that re...
CHEDDA syndrome stands for congenital hypotonia, epilepsy, developmental delay and digital anomalies. Is a newly discovered neurodevelopmental syndrome associated with mutations in a conserved histidine-rich motif within Atrophin-1 (ATN-1).1
CHEDDA syndrome is very rare, with only...
Transient osteoporosis is a self-limited condition characterized by reparative bone remodeling, which can affect all weight-bearing joints, being most common in the femoral head. For detailed description of that condition see transient ostoporosis of the hip.
Impingement syndrome is a painful encroachment of joint motion caused by protruding bony or soft tissue structures.
Impingement syndromes are common and can occur at any age.
developmental osseous anomalies
Little league shoulder is thought to occur due to overuse damage of the proximal humeral epiphysis/metaphysis, seen typically in young baseball players, especially pitchers.
Although it is most commonly seen in baseball players particularly in pitchers, it also presents in adolesc...
Bile plug syndrome, also known as inspissated bile syndrome, is an uncommon cause of jaundice in neonates. Refers to a rare extrahepatic mechanical obstruction of the major bile duct in the perinatal period caused by viscous bile (sludge) within its lumen 3.
Anterior suprapatellar (quadriceps) fat pad impingement syndrome is a controversial cause of anterior knee pain although anterior suprapatellar fat pad edema may often, and possibly more commonly, be incidental 1,2.
The anterior suprapatellar fat pad is edematous c...
Toxic shock syndrome (TSS) is a severe bacterial-toxin mediated condition, characterized by an initial soft tissue infection, which rapidly progresses to systemic disease and circulatory collapse 5. It is due to a Gram positive infection, most frequently Staphylococcus aureus or Streptococcus py...
Central herniation is the subtype of downward transtentorial herniation of the brain that involves descent of the diencephalon and midbrain. It usually occurs with other types of downward herniation such as uncal herniation.
The clinical syndrome of central herniation c...
Vaughan-Jackson syndrome describes a rare syndrome of sequential atraumatic extensor tendon ruptures in the hand, usually in the setting of rheumatoid arthritis of the distal radioulnar joint.
The presentation is with reduced extension of the fingers 1-5. Typically, the f...
Small for size syndrome (SFSS) is a clinical syndrome caused by the transplantation of a liver graft that is too small for a recipient. It occurs when the graft‐to‐recipient weight ratio (GRWR ) is less than 0.8% or a graft volume to standard liver volume ratio (GV/SLV) is less than 35%.
Lesch-Nyhan syndrome is a rare X-linked genetic disease caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT).
Affects 1 per 380,000 individuals, which are nearly all male given the X-linked inheritance 1.
Hunter syndrome, also known as mucopolysaccharidosis type II (MPS II) is a rare genetic mucopolysaccharidosis disorder characterized by specific clinical features 1.
Hunter syndrome is an X-linked recessive disease and therefore much more common in males. It is a rare disorder wit...
Computer vision syndrome is a condition that affects primarily workers who use computers (including tablets and other devices with computer screens) many hours a day with symptoms that can include blurred vision, eye strain, and headache.
Computer vision syndrome is a growing phen...
Bone marrow edema syndrome refers to a group of transient, self-limiting clinical entities of unknown cause, which are associated with the presence of bone marrow edema pattern.
These conditions include:
transient osteoporosis of the hip
bone marrow edema syndrome of the foot and ankle
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.
Anterior resection syndrome refers to wide spectrum of symptoms which develop post-sphincter preserving rectal resection for rectal cancer.
Pelvic radiotherapy is a known risk factor to develop anterior resection syndrome.
There have been reports that up to 47% of patients who un...
Branchio-otic syndrome (also known as BOS, BOS1, BO syndrome 1 and branchiootic dysplasia) is a rare autosomal dominant disease. It manifests as abnormalities of the second branchial arch, with predominant abnormalities of the ear. No renal disease is seen, in contradistinction to its close name...
The severe acute respiratory syndrome (SARS) is a zoonotic illness caused by severe acute respiratory syndrome-related coronavirus (SARS-CoV-1), a coronavirus. The disease was first seen in the city of Foshan in Guangdong Province in China in 2002 and was traced back to the Himalayan (masked) p...
Wolfram syndrome type one, also known as DIDMOAD, is a disease caused by an autosomal recessive genetic trait, caused by mutations in the WFS1 gene, with incomplete penetrance.
The syndrome presents with early onset of insulin-dependent diabetes mellitus, progressive optic atrophy, diabetes ins...
Episodic angioedema with eosinophilia (EAE), also known as Gleich syndrome, is a rare condition presenting as a self-limiting cyclic urticaria, fever, angioedema, weight gain and marked eosinophilia, with 3-4 weekly episodes 1.
Episodic angioedema with eosinophilia is rare, only a...
Trisomy 8 mosaicism or Warkany syndrome is a less severe variant of trisomy 8 and individuals with a low proportion of affected cells may exhibit a comparatively mild range of physical abnormalities and developmental delay. They are more likely to survive into childhood and adulthood but can exh...
Big black brain is a radiologic pattern unique to infants and toddlers in the context of traumatic brain injury, most frequently due to abusive head trauma.
The CT presentation is a parenchymal hypodensity and uniform loss of gray-white differentiation in the entire hemisphere, associated with...
Perry syndrome is a rare, progressive, hereditary neurodegenerative movement disorder and TDP-43 proteinopathy.
Perry syndrome is considered to be very rare, generally isolated to select families who carry the mutation implicated in the disease 1,2. In one study, the age on onset ...
Agraphia represents acquired impairments of writing ability secondary to damage or dysfunction of the central nervous system. Impairments caused solely by motor dysfunction (e.g. hand paresis or tremor) are not considered to be forms of agraphia 1.
Agraphia is rarely an i...
Alexia (or acquired dyslexia) is a neurological term refers to an acquired impairment of reading resulting from damage of critical brain areas.
Alexia can manifest itself as an impairment of oral reading and reading comprehension alike and can occur in combination with va...
Obstructive sleep apnea (OSA), also known as obstructive sleep apnea syndrome (OSAS), is a disorder characterized by repetitive episodes of total (i.e. apnoeas) or reduction (i.e. hypopnoeas) in ventilation due to total or partial collapse of the upper airway during sleep.
This condition is dis...
Shapiro syndrome is a very rare condition characterized by the triad of episodic hypothermia, hyperhidrosis, and agenesis of the corpus callosum 1. A similar syndrome, characterized by episodic hyperthermia and agenesis of the corpus callosum, has been termed reverse Shapiro syndrome 2.
RAPADILINO syndrome is a rare autosomal-recessive syndrome that results from mutations in the RECQL4 gene 1.
RAPADILINO syndrome is a rare condition, prevalence is unknown. It is, however, more common and was first described in Finnish populations 2.
The acronym RAPADI...
Schindler disease is a rare lysosomal storage disorder characterized by deficiency of alpha-N-acetylgalactosaminidase (alpha-NAGA or alpha-galactosidase B).
It is a rare disease with autosomal recessive inheritance.
Age and severity of presentation depends ...
Sanjad Sakati syndrome, also known as hypoparathyroidism-intellectual disability-dysmorphism syndrome, is a rare autosomal recessive disorder.
The syndrome is almost exclusively found in people of Arab origin. There is an equal distribution in both sexes.
White cord syndrome refers to the sudden onset of neurological deterioration following spinal decompressive surgery. The condition is believed to be a form of reperfusion injury of the spinal cord, not to be confused with central cord syndrome.
White cord syndrome is rare with onl...
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...
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.
Persistent postural-perceptual dizziness refers to a recently (c. 2017) defined diagnostic syndrome. It unifies key features of chronic subjective dizziness, phobic postural vertigo and related disorders. It produces persistent dizziness, non-spinning vertigo and/or unsteadiness.
The empty nose syndrome refers to a paradoxical sensation of nasal obstruction despite objectively patent nasal airways following inferior and/or middle turbinate resection.
The condition is rare, occuring in a minority of patients who have undergone prior turbinate resection.
Superior thyroid cornu syndrome refers to a situation when there is precipitation of dysphagia and /or other symptoms as a hypertrophy +/- ossification of one of both the both of the superior horns (cornu) of the thyroid cartilage. This can also result from extreme medial deviation.
There are several autoinflammatory diseases with periodic fevers. These include
familial mediterranean fever (FMF)
cryopyrin-associated periodic syndrome (CAPS)
tumor necrosis factor receptor-associated periodic fever syndrome (TRAPS)
hyperimmunoglobulinemia D and periodic fever syndrome / m...
Tumor necrosis factor receptor-associated periodic syndrome (or sometimes abbreviated as TRAPS) is a condition characterized by recurrent (periodic) episodes of fever as well as a spectrum of dermatologic findings that includes migratory patches, edematous plaques, periorbital edema, and/or conj...
Peroxisome biogenesis disorders (PBDs) are autosomal recessive, inborn errors of peroxisomes, a eukaryotic cell organelle critical to the breakdown of very long chain fatty acids via beta-oxidation.
There are two main groups 1:
Zellweger spectrum disorder (ZSD)
Robinow-Sorauf syndrome (RSS) is a rare, autosomal dominant type of acrocephalosyndactyly syndrome (ACS).
Rather than being a distinct ACS, it has now generally accepted that RSS is, in fact, part of the Saethre-Chotzen syndrome phenotypic spectrum 1. This is due to similar phenotype and both b...
Pickardt syndrome also known as Pickardt-Fahlbusch syndrome is a rare syndrome characterized by tertiary hypothyroidism, hyperprolactinemia and other pituitary hormone deficiencies resulting from interruption of the portal blood supply of the anterior pituitary via the infundibulum which drains ...
Börjeson-Forssman-Lehmann syndrome (BFLS) is an extremely rare disorder characterized by
gonadal failure (testes in males or the ovaries in females) to produce hormones (hypogonadism)
distinctive facial features.
Affected infants tend to experience ...
Cerebellar mutism syndrome, also known as post-operative pediatric cerebellar mutism syndrome (pCMS), usually develops after resection of midline cerebellar or intraventricular tumors in the posterior cranial fossa. Typical features of this condition are transient mutism, ataxia, hypotonia and i...
Subacute encephalopathy with seizures in alcoholics (SESA syndrome) is a rare complication of chronic excessive alcohol consumption that can present with seizures and a variety of neurological deficits.
SESA syndrome is rare and seen in alcoholics who are not undergoing withdrawa...
Bone marrow edema syndrome of the foot and ankle, also known as transient bone marrow edema syndrome of the foot and ankle, refers to the presence of self-limited, patchy bone marrow T2 hyperintensities in the bones of the ankle and/or foot of unknown etiology. It is related to transient osteopo...
Branchio-oculo-facial syndrome (BOFS) is a very rare autosomal dominant genetic disorder that is characterized clinically by abnormalities affecting the eyes, craniofacial structures, and branchial sinuses.
More than 80 cases have been reported in the global literature since its f...
Adductor canal syndrome (also known as adductor canal compression syndrome) is a rare, non-atherosclerotic cause of arterial occlusion and limb ischemia 1. There is compression of the superficial femoral artery (SFA) in the adductor canal.
External compression of the superficial f...
Sepsis is a syndrome, with a poorly understood pathogenesis, characterized clinically by a recognized set of signs and symptoms in someone with presumed infection.
Sepsis was defined by The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) in 2016 as ...
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a rare neurodegenerative balance disorder characterized by cerebellar ataxia, sensory neuronopathy (ganglionopathy), and bilateral vestibular hypofunction.
The epidemiology is yet to be defined, but CA...
Familial atypical multiple mole melanoma (FAMMM) syndrome is an autosomal dominant genodermatosis characterized by multiple melanocytic nevi (often more than 50) and a family history of melanoma.
It is associated with mutations in the CDKN2A gene and shows reduced penetranc...