Epignathus is a rare teratoma of the oropharynx. [1] Epignathus is a form of oropharyngeal teratoma that arises from the palate and, in most cases, results in death. The pathology is thought to be due to unorganized and uncontrolled differentiation of somatic cells leading to formation of the teratoma; sometimes it is also referred to as "fetus-in-fetu", which is an extremely rare occurrence of an incomplete but parasitic fetus located in the body of its twin. [2] [3] This tumor is considered benign but life-threatening because of its atypical features (size, location, and rate of development) and high risk of airway obstruction, which is the cause of death in 80-100% of the cases at the time of delivery. [1]
Despite the high mortality rate, the most important factor in improving survival probability is to detect and diagnose the lesion before birth using ultrasound and MRI scans. [4] If undetected prenatally, the epignathus will be apparent immediately after birth, but prognosis will be poor due to lack of preparation and treatment plans. [1] Most babies with epignathus have a poor prognosis due to late diagnosis and, subsequently, complications in securing the airway. [2] However, with early detection and multidisciplinary healthcare teams, an adequate treatment plan to secure the baby's airway and surgically remove the lesion may improve the prognosis. [2] Treatment options for this rare condition prioritize managing the risk of asphyxiation prior to deciding on an appropriate plan for the teratoma resection. [5]
Teratomas, which are generally benign tumors, originate from stem cells, with the oropharynx (epignathus) region being the second most common location for head and neck teratomas. [2] The tumor arises from the palato-pharyngeal region around the basisphenoid (Rathke's pouch), or most commonly the base of the skull. [6] Epignathi are present from birth and has been shown to affect all three germ layers (ectodermal, mesodermal, and endodermal layers) and can include cartilage, bone, and fat. [1] [2] Case reports describe the possibility for an epignathus to present as an incompletely formed and parasitic fetal twin, which is called "fetus-in-fetu". [7] Many case reports about babies with epignathus have reported common malformations of cleft palate, and bifid tongue and/or nose. [1] [2] The tumor can grow within the oral cavity and protrude out of the mouth, causing obstruction of the airway and therefore mortality. [8] This lesion may be associated with polyhydramnios, or excessive amniotic fluid around the fetus, and typically prevents the fetus from swallowing the amniotic fluid. In rare cases, the tumor may extend into the cranial cavity, including into the brain, or it may become encapsulated the cranial cavity and not enter the brain at all. [9] Most neonates and young children who present with epignathus have exhibited benign tumors, in comparison to older children and adults who have presented with more malignant teratomas. [2]
Recent findings have shown some genetic abnormalities associated with epignathi. [9] There have been case reports noting chromosomal irregularities such as a 49,XXXXY karyotype, [10] duplication of 1q and 19p, [11] and ring X chromosome mosaicism. [12] However, this theory is still inconclusive, as there have been other studies that have shown no chromosomal abnormalities. [13]
Teratomas develop in the head and neck region with a live birth (fetus shows signs of life after leaving mother's womb) incidence of 1:20,000 to 40,000. [14] Due to the rarity of epignathus, the information gathered regarding incidence and prevalence is sourced from case reports. The occurrence of epignathus, a teratoma of the oropharynx, is extremely rare, with a live birth incidence found to be 1:35,000 to 1:200,000. [1] Of the reported cases, epignathus was found to be more common in females than in males (3:1 ratio); however, there is a lack of evidence demonstrating that an individual's genetic makeup will increase the likelihood of developing this form of teratoma. [15] The studies have shown having one child with epignathus does not increase the chances of having pregnancies with this disease in the future. [16] An estimated 10% of most epignathus diagnoses also report epignathus-related abnormalities and deformities such as the formation of a cleft palate (split in the mouth's roof due to abnormal fusing of the hard palate during fetal development), hemangiomas (pathological development of extra blood vessels), and more. [17] [2]
Epignathus occurs at a critical location, which makes this tumor extremely dangerous and not resectable in newborn children. One of the primary modalities that can be used for diagnosing teratoma and epignathus is ultrasound. Diagnosis of epignathus may be made before the birth of the child by using ultrasound. Sonography evaluation is essential during pregnancy for diagnosing epignathus and perhaps surgically removing the teratoma while the child is still in the womb. [3] One of the main characteristics of epignathus in the sonography evaluation is a relatively large mass that can be seen in the anterior or front side of the neck. [3] [8] For diagnosing epignathus, radiography, which is an imaging tool for bones and skeleton, might not be beneficial, as no skeletal abnormalities have been noted in several cases of epignathus. Microscopic examination of the tumor may be of benefit. The microscopic examination focuses on the pattern of cell growth (histology). Because epignathus is a type of teratoma, it has a unique histological structure. Hence, the pattern found in microscopic examination can show a growth pattern consistent with teratoma. [4] Another method that can be used to diagnose epignathus is karyotyping, which shows genetic abnormalities in the fetus. However, the parents' chromosomes are healthy, and there is no evidence of it being inherited genetically[ clarification needed ]. [16] Epiganthus is a very rare condition that results in the studies on it to primarily be case studies. In some of these case reports, it was seen that the diagnosis of epignathus occurred as early as 17 weeks from conception. [16] However, in other case studies, the ultrasound was normal at 17 weeks. If the tumor is small enough, it might appear at the delivery unpredicted or even later on, in a child. [16] For example, in one case, epignathus was detected at week 28, which caused change in the structure of face and airways, and the child was born in week 34 with Caesarean section and needed assistance for breathing. [18] If the diagnosis of epignathus does not happen during pregnancy, and the baby survives to birth, even though it becomes immediately apparent, there is a low chance for survival. [8] Other clinical features include dyspnoea, cyanosis, and difficulty in breathing, sucking and swallowing due to the presence of the tumor. [8]
The main priority for treating epignathus is to establish a usable airway free of obstruction and then to feed the baby. [19] [20] This is frequently difficult because there are often complications due to the large mass of the tumor, its location, the complex progression and required corrective modifications. [1] These tumors, characterized as unusual masses or lumps of tissue, are often the result of abnormal tissue growth and may remain localized in one area or spread to other parts of the body.
However, diagnostic imaging tools such as 3-D ultrasonography and magnetic resonance imaging (MRI) have been essential in early detection of tumors in the head and neck region of the fetus. [2] Although few cases have been treated successfully, early prenatal detection and intervention prior to birth has proven to be key in order to have a chance to save the baby's life. [9]
3-D ultrasonography works to create an image by producing high frequency sound waves throughout the body in order to detect and receive echo sound. These echoes are then interpreted to form an image depending on how strong the echo was and how long the echo was received after the sound waves were transmitted. Compared to other imaging techniques that use radioactive dyes or ionizing radiation, ultrasounds have been considered safe. [21] The use of 3-D ultrasonography has allowed surgeons to pinpoint the exact position of organs and tissues within the body and has been proven vital for surgical guidance especially when treating transplant and cancer. [22] Magnetic resonance imaging (MRI) is another medical imaging technique that uses strong magnetic fields and radio waves to create images of organs and tissues within the body. [23] It is important to understand that MRI does not involve x-rays or ionizing radiation, which makes it a better and safer choice for medical imaging compared to CT and PET scans. [23] The use of these diagnostic tools during fetal development are important for early detection of any abnormal masses that may turn out to be tumors.
If tumors are detected early using the featured diagnostic tools, the baby should be stabilized before surgical removal is conducted to repair the abnormalities. [5] In order to stabilize the baby, the umbilical cord is kept intact to provide oxygen to the fetus in case of airway obstruction. [5] This is important in the case that a tracheostomy, or operation required to allow air to enter the lungs, is required in order to save the baby's life. [5] Only after the airway is secured should the umbilical cord be clamped and the baby can proceed with surgery. [5] During surgery, a complete repair and removal procedure of the diseased tissues, especially those that may spread throughout the body, is necessary in order to prevent any chance of reoccurrence after a period of improvement. [2] Following surgery, chemotherapy may be used to promote residual tumor regression. [9]
In some cases, because of the complications of the epignathus tumor, terminating the pregnancy might be an option that needs to get discussed. [16]
Epignathus diagnoses have a very poor prognosis or outcome with a death rate of 80–100% in newborn babies (either before delivery or shortly after delivery), primarily due to asphyxiation or suffocation from the tumor blocking the baby's airway. [15] [3] The course of the disease and outcome are dependent on many factors including size, location, and rate of development of the teratoma, all of which affect the magnitude of airway obstruction. [24] Other complications such as the deformation of facial structure or deformation of jaw structure may impact the baby's ability to swallow and breathe, which may also negatively impact the prognosis as well. [15] If the tumors are large, they might cause changes in the structure of face, nose and upper lips, to the point that they cannot be identified. [16] Factors that may improve survival rates include early diagnosis of epignathus before birth, multidisciplinary management in preventing obstruction in the airways, and feasibility in surgical removal of the teratoma. [25] [26] The prognosis can result in broad range of outcomes. In some cases, pregnancies were terminated after the fetus was diagnosed with epignathus for different complications. The most common reason was that the tumor was continuing to spread even further in the head and mouth area. [16] Very few long term survivors have been reported so the prognosis past the neonatal period is unclear. [27]
Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.
Colpocephaly is a cephalic disorder involving the disproportionate enlargement of the occipital horns of the lateral ventricles and is usually diagnosed early after birth due to seizures. It is a nonspecific finding and is associated with multiple neurological syndromes, including agenesis of the corpus callosum, Chiari malformation, lissencephaly, and microcephaly. Although the exact cause of colpocephaly is not known yet, it is commonly believed to occur as a result of neuronal migration disorders during early brain development, intrauterine disturbances, perinatal injuries, and other central nervous system disorders. Individuals with colpocephaly have various degrees of motor disabilities, visual defects, spasticity, and moderate to severe intellectual disability. No specific treatment for colpocephaly exists, but patients may undergo certain treatments to improve their motor function or intellectual disability.
Cebocephaly is a developmental anomaly that is part of a group of defects called holoprosencephaly. Cebocephaly involves the presence of two separate eyes set close together and a small, flat nose with a single nostril. It may be diagnosed before or after birth. It has a very poor prognosis, with most affected infants dying soon after birth. It is very rare, having been estimated to affect around 1 in 40,000 deliveries.
Iniencephaly is a rare type of cephalic disorder characterised by three common characteristics: a defect to the occipital bone, spina bifida of the cervical vertebrae and retroflexion of the head on the cervical spine. Stillbirth is the most common outcome, with a few rare examples of live birth, after which death invariably occurs within a short time.
A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone. Teratomata typically form in the tailbone, ovary, or testicle.
Prenatal testing is a tool that can be used to detect some birth defects at various stages prior to birth. Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of the zygote, embryo, or fetus, either before gestation even starts or as early in gestation as practicable. Screening can detect problems such as neural tube defects, chromosome abnormalities, and gene mutations that would lead to genetic disorders and birth defects, such as spina bifida, cleft palate, Down syndrome, trisomy 18, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, muscular dystrophy, and fragile X syndrome. Some tests are designed to discover problems which primarily affect the health of the mother, such as PAPP-A to detect pre-eclampsia or glucose tolerance tests to diagnose gestational diabetes. Screening can also detect anatomical defects such as hydrocephalus, anencephaly, heart defects, and amniotic band syndrome.
Oligohydramnios is a medical condition in pregnancy characterized by a deficiency of amniotic fluid, the fluid that surrounds the fetus in the abdomen, in the amniotic sac. It is typically diagnosed by ultrasound when the amniotic fluid index (AFI) measures less than 5 cm or when the single deepest pocket (SDP) of amniotic fluid measures less than 2 cm. Amniotic fluid is necessary to allow for normal fetal movement, lung development, and cushioning from uterine compression. Low amniotic fluid can be attributed to a maternal, fetal, placental or idiopathic cause and can result in poor fetal outcomes including death. The prognosis of the fetus is dependent on the etiology, gestational age at diagnosis, and the severity of the oligohydramnios.
Hydrops fetalis or hydrops foetalis is a condition in the fetus characterized by an accumulation of fluid, or edema, in at least two fetal compartments. By comparison, hydrops allantois or hydrops amnion is an accumulation of excessive fluid in the allantoic or amniotic space, respectively.
Hydronephrosis describes hydrostatic dilation of the renal pelvis and calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dilation of the entire upper urinary tract.
The EXIT procedure, or ex utero intrapartum treatment procedure, is a specialized surgical delivery procedure used to deliver babies who have airway compression. Causes of airway compression in newborn babies result from a number of rare congenital disorders, including bronchopulmonary sequestration, congenital cystic adenomatoid malformation, mouth or neck tumor such as teratoma, and lung or pleural tumor such as pleuropulmonary blastoma. Airway compression discovered at birth is a medical emergency. In many cases, however, the airway compression is discovered during prenatal ultrasound exams, permitting time to plan a safe delivery using the EXIT procedure or other means.
Sacrococcygeal teratoma (SCT) is a type of tumor known as a teratoma that develops at the base of the coccyx (tailbone) and is thought to be primarily derived from remnants of the primitive streak. Sacrococcygeal teratomas are benign 75% of the time, malignant 12% of the time, and the remainder are considered "immature teratomas" that share benign and malignant features. Benign sacrococcygeal teratomas are more likely to develop in younger children who are less than 5 months old, and older children are more likely to develop malignant sacrococcygeal teratomas.
A cystic hygroma is an abnormal growth that usually appears on a baby's neck or head. It consists of one or more cysts and tends to grow larger over time. The disorder usually develops while the fetus is still in the uterus, but can also appear after birth.
The Pallister–Killian syndrome (PKS), also termed tetrasomy 12p mosaicism or the Pallister mosaic aneuploidy syndrome, is an extremely rare and severe genetic disorder. PKS is due to the presence of an extra and abnormal chromosome termed a small supernumerary marker chromosome (sSMC). sSMCs contain copies of genetic material from parts of virtually any other chromosome and, depending on the genetic material they carry, can cause various genetic disorders and neoplasms. The sSMC in PKS consists of multiple copies of the short arm of chromosome 12. Consequently, the multiple copies of the genetic material in the sSMC plus the two copies of this genetic material in the two normal chromosome 12's are overexpressed and thereby cause the syndrome. Due to a form of genetic mosaicism, however, individuals with PKS differ in the tissue distributions of their sSMC and therefore show different syndrome-related birth defects and disease severities. For example, individuals with the sSMC in their heart tissue are likely to have cardiac structural abnormalities while those without this sSMC localization have a structurally normal heart.
Ventriculomegaly is a brain condition that mainly occurs in the fetus when the lateral ventricles become dilated. The most common definition uses a width of the atrium of the lateral ventricle of greater than 10 mm. This occurs in around 1% of pregnancies. When this measurement is between 10 and 15 mm, the ventriculomegaly may be described as mild to moderate. When the measurement is greater than 15mm, the ventriculomegaly may be classified as more severe.
Pierre Robin sequence is a congenital defect observed in humans which is characterized by facial abnormalities. The three main features are micrognathia, which causes glossoptosis, which in turn causes breathing problems due to obstruction of the upper airway. A wide, U-shaped cleft palate is commonly also present. PRS is not merely a syndrome, but rather it is a sequence—a series of specific developmental malformations which can be attributed to a single cause.
Cat-eye syndrome (CES) or Schmid–Fraccaro syndrome is a rare condition caused by an abnormal extra chromosome, i.e. a small supernumerary marker chromosome. This chromosome consists of the entire short arm and a small section of the long arm of chromosome 22. In consequence, individuals with the cat-eye syndrome have three (trisomic) or four (tetrasomic) copies of the genetic material contained in the abnormal chromosome instead of the normal two copies. The prognosis for patients with CES varies depending on the severity of the condition and their associated signs and symptoms, especially when heart or kidney abnormalities are seen.
Fetal echocardiography, or Fetal echocardiogram, is the name of the test used to diagnose cardiac conditions in the fetal stage. Cardiac defects are amongst the most common birth defects. Their diagnosis is important in the fetal stage as it might help provide an opportunity to plan and manage the baby as and when the baby is born. Not all pregnancies need to undergo fetal echo.
Pulmonary hypoplasia is incomplete development of the lungs, resulting in an abnormally low number or small size of bronchopulmonary segments or alveoli. A congenital malformation, it most often occurs secondary to other fetal abnormalities that interfere with normal development of the lungs. Primary (idiopathic) pulmonary hypoplasia is rare and usually not associated with other maternal or fetal abnormalities.
Congenital pulmonary airway malformation (CPAM), formerly known as congenital cystic adenomatoid malformation (CCAM), is a congenital disorder of the lung similar to bronchopulmonary sequestration. In CPAM, usually an entire lobe of lung is replaced by a non-working cystic piece of abnormal lung tissue. This abnormal tissue will never function as normal lung tissue. The underlying cause for CPAM is unknown. It occurs in approximately 1 in every 30,000 pregnancies.
Pulmonary agenesis is an inborn lung underdevelopment that is rare and potentially lethal. The disorder is caused by a complete developmental arrest of the primitive lung during embryonic life, and it is often associated with other developmental defects. Bilateral and unilateral pulmonary agenesis are classified, depending on whether one side of the lung or both sides are affected. Bilateral pulmonary agenesis is lethal, while the mortality rate of unilateral pulmonary agenesis is higher than 50%. Depending on the severity, the symptom ranges from none to various respiratory complaints. It is detectable prenatally, however, its nonspecific clinical features act as the obstacle for diagnosing. The exact cause of pulmonary agenesis is still obscure. However, theories have been raised regarding the vascular, iatrogenic, viral and genetic causes of pulmonary agenesis in an attempt to explain the pathogenesis of the disorder. In most cases of pulmonary agenesis, surgical resection is performed to remove the malformed lobe or the entire defected lung of the patient depending on the severity of the respiratory impairment.
{{cite journal}}
: Cite journal requires |journal=
(help){{cite journal}}
: CS1 maint: DOI inactive as of January 2024 (link)