Lymphangioma
Encyclopedia
Lymphangiomas are malformations of the lymphatic system
, which is the network of vessels responsible for returning to the venous system excess fluid from tissues. These malformations can occur at any age and may involve any part of the body, but 90% occur in children less than 2 years of age and involve the head and neck. These malformations are either congenital or acquired. Congenital lymphangiomas are often associated with chromosomal abnormalities such as Turner syndrome
, although they can also exist in isolation. Lymphangiomas are commonly diagnosed before birth using fetal ultrasonography. Acquired lymphangiomas may result from trauma, inflammation, or lymphatic obstruction.
Most lymphangiomas are benign lesions that result only in a soft, slow-growing, "doughy" mass. Since they have no chance of becoming malignant, lymphangiomas are usually treated for cosmetic reasons only. Rarely, impingement upon critical organs may result in complications, such as respiratory distress
when a lymphangioma compresses the airway. Treatment includes aspiration
, surgical excision, laser
and radiofrequency ablation
, and sclerotherapy
.
Capillary lymphangiomas
Cavernous lymphangiomas
Cystic hygromas
Hemangiolymphangioma
Lymphangiomas may also be classified into microcystic, macrocystic, and mixed subtypes, according to the size of their cysts.
Microcystic lymphangiomas
Macrocystic lymphangiomas
Mixed lymphangiomas
Finally, lymphangiomas may be described in stages, which vary by location and extent of disease. In particular, stage depends on whether lymphangiomas are present above or superior to the hyoid bone
(suprahyoid), below or inferior to the hyoid bone (infrahyoid), and whether the lymphangiomas are on one side of the body (unilateral) or both (bilateral).
Stage I: Unilateral infrahyoid.
Stage II: Unilateral suprahyoid.
Stage III: Unilateral suprahyoid and infrahyoid.
Stage IV: Bilateral suprahyoid.
Stage V: Bilateral suprahyoid and infrahyoid.
develops, although symptoms may not become visible until after the baby is born. This blockage is thought to be caused by a number of factors, including maternal alcohol use
and viral infections during pregnancy. Why the embryonic lymph sacs remain disconnected from the rest of the lymphatic system is not known.
Cystic lymphangioma that emerges during the first two trimesters of pregnancy is associated with genetic disorders such as Noonan syndrome
and trisomies 13
, 18
, and 21. Chromosomal aneuploidy
such as Turner syndrome
or Down syndrome
were found in 40% of patients with cystic hygroma.
of lymphangioma circumscriptum, finding lymphatic cisterns in the deep subcutaneous plane are separated from the normal network of lymph vessels. They communicate with the superficial lymph vesicles through vertical, dilated lymph channels. Whimster theorized the cisterns might come from a primitive lymph sac that failed to connect with the rest of the lymphatic system during embryonic development.
A thick coat of muscle fibers that cause rhythmic contractions line the sequestered primitive sacs. Rhythmic contractions increase the intramural pressure, causing dilated channels to come from the walls of the cisterns toward the skin. He suggested that the vesicles seen in lymphangioma circumscriptum are outpouchings of these dilated projecting vessels.
Lymphatic and radiographic studies support Whimsters observations. Such studies reveal that big cisterns extend deeply into the skin and beyond the clinical lesions. Lymphangiomas that are deep in the dermis show no evidence of communication with the regular lymphatics. The cause for the failure of lymph sacs to connect with the lymphatic system is not known.
Microscopically, the vesicles in lymphangioma circumscriptum are greatly dilated lymph channels that cause the papillary dermis to expand. They may be associated with acanthosis
and hyperkeratosis
. There are many channels in the upper dermis which often extend to the subcutis (the deeper layer of the dermis, containing mostly fat and connective tissue). The deeper vessels have large calibers with thick walls which contain smooth muscle
. The lumen is filled with lymphatic fluid, but often contains red blood cells, lymphocytes, macrophages, and neutrophils. The channels are lined with flat endothelial cells. The interstitium has many lymphoid cells and shows evidence of fibroplasia (the formation of fibrous tissue). Nodules (A small mass of tissue or aggregation of cells) in cavernous lymphangioma are large, irregular channels in the reticular dermis and subcutaneous tissue that are lined by a single layer of endothelial cells. Also an incomplete layer of smooth muscle also lines the walls of these channels. The stroma consists of loose connective tissue with a lot of inflammatory cells. These tumors usually penetrate muscle. Cystic hygroma is indistinguishable from cavernous lymphangiomas on histology.
The typical history of Lymphangioma circumscriptum shows a small number of vesicles on the skin at birth or shortly after. In subsequent years, they tend to increase in number, and the area of skin involved continues to expand. Vesicles or other skin abnormalities may not be noticed until several years after birth. Usually, lesions are asymptomatic or do not show any evidence of a disease, but, mostly, patients may have random break outs of some bleeding and major drainage of clear fluid from ruptured vesicles.
Cavernous lymphangioma first appears during infancy, when a rubbery nodule with no skin changes becomes obvious in the face, trunk, or extremity. These lesions often grow at a rapid pace, similar to that of raised hemangioma
s. No family history of prior lymphangiomas is described.
Cystic hygroma
causes deep subcutaneous cystic swelling, usually in the axilla, base of the neck, or groin, and is typically noticed soon after birth. If the lesions are drained, they will rapidly fill back up with fluid. The lesions will grow and increase to a larger size if they are not completely removed in surgery.
, and lymph fluid leakage. Two cases of lymphangiosarcoma
arising from lymphangioma circumscriptum
have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy
.
In cystic hygroma, large cysts can cause dysphagia
, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis
to determine if they have chromosomal abnormalities, and parents should receive genetic counseling
because this condition can recur in subsequent pregnancies.
Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma.
Cystic Hygroma can be treated with OK432 (Picibanil)
The least invasive and most effective form of treatment is now performed by interventional radiologists. A sclerosing agent, such as 1% or 3% sodium tetradecyl sulfate, doxycycline, or ethanol, may be directly injected injected into a lymphocele. "All sclerosing agents are thought to work by ablating the endothelial cells of the disrupted lymphatics feeding into the lymphocele."
Lymphangioma circumscription can be healed when treated with a flashlamp pulsed dye laser
, although this can cause port-wine stains and other vascular lesions.
Treatment for cystic hygroma involves the removal of the abnormal tissue; however complete removal may be impossible without removing other normal areas. Surgical removal of the tumor is the typical treatment provided, with the understanding that additional removal procedures will most likely be required as the lymphangioma grows. Most patients need at least two procedures done for the removal process to be achieved. Recurrence is possible but unlikely for those lesions able to be removed completely via excisional surgery. Radiotherapy and chemical cauteries are not as effective with the lymphangioma than they are with the hemangioma
.
inspection. In prenatal cases, cystic lymphangioma is diagnosed using an ultrasound
; when confirmed amniocentesis
may be recommended to check for associated genetic disorders.
"hygroth" meaning fluid and "oma" meaning tumor. In 1965, Bill and Summer proposed that cystic hygromas and lymphangiomas are variations of a single entity and that its location determines its classification.
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
, which is the network of vessels responsible for returning to the venous system excess fluid from tissues. These malformations can occur at any age and may involve any part of the body, but 90% occur in children less than 2 years of age and involve the head and neck. These malformations are either congenital or acquired. Congenital lymphangiomas are often associated with chromosomal abnormalities such as Turner syndrome
Turner syndrome
Turner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent...
, although they can also exist in isolation. Lymphangiomas are commonly diagnosed before birth using fetal ultrasonography. Acquired lymphangiomas may result from trauma, inflammation, or lymphatic obstruction.
Most lymphangiomas are benign lesions that result only in a soft, slow-growing, "doughy" mass. Since they have no chance of becoming malignant, lymphangiomas are usually treated for cosmetic reasons only. Rarely, impingement upon critical organs may result in complications, such as respiratory distress
Respiratory distress
Respiratory distress may refer to either/both:* Labored breathing, the physical presentation of respiratory distress*Shortness of breath or dyspnea - a sensation of respiratory distress-See also:*List of terms of lung size and activity...
when a lymphangioma compresses the airway. Treatment includes aspiration
Aspiration
Aspiration may refer to:In linguistics:*Aspirated consonant, a plosive pronounced with a strong burst of air*Debuccalization, the conversion of a consonant to [h] or [ʔ]*Voiceless glottal fricative In engine technology:...
, surgical excision, laser
Laser ablation
Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma...
and radiofrequency ablation
Radiofrequency ablation
Radio frequency ablation is a medical procedure where part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from the high frequency alternating current to treat a medical disorder...
, and sclerotherapy
Sclerotherapy
Sclerotherapy is a procedure used to treat blood vessels or blood vessel malformations and also those of the lymphatic system. A medicine is injected into the vessels, which makes them shrink. It is used for children and young adults with vascular or lymphatic malformations...
.
Classification
Lymphangiomas have traditionally been classified into three subtypes: capillary and cavernous lymphangiomas and cystic hygromas. This classification is based on their microscopic characteristics. A fourth subtype, the hemangiolymphangioma is also recognized.Capillary lymphangiomas
- Capillary lymphangiomas are composed of small, capillary-sized lymphatic vessels and are characteristically located in the epidermisEpidermis (zoology)The Epidermis is an epithelium that covers the body of an eumetazoan . Eumetazoa have a cavity lined with a similar epithelium, the gastrodermis, which forms a boundary with the epidermis at the mouth.Sponges have no epithelium, and therefore no epidermis or gastrodermis...
.
Cavernous lymphangiomas
- Composed of dilated lymphatic channels, cavernous lymphangiomas characteristically invade surrounding tissues.
Cystic hygromas
- Cystic hygromas are large, macrocystic lymphangiomas filled with straw-colored, protein-rich fluid.
Hemangiolymphangioma
- As suggested by their name, hemangiolymphangiomas are lymphangiomas with a vascular component.
Lymphangiomas may also be classified into microcystic, macrocystic, and mixed subtypes, according to the size of their cysts.
Microcystic lymphangiomas
- Microcystic lymphangiomas are composed of cysts, each of which measures less than 2 cm3 in volume.
Macrocystic lymphangiomas
- Macrocystic lymphangiomas contain cysts measuring more than 2 cm3 in volume.
Mixed lymphangiomas
- Lymphangiomas of the mixed type contain both microcystic and macrocystic components.
Finally, lymphangiomas may be described in stages, which vary by location and extent of disease. In particular, stage depends on whether lymphangiomas are present above or superior to the hyoid bone
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
(suprahyoid), below or inferior to the hyoid bone (infrahyoid), and whether the lymphangiomas are on one side of the body (unilateral) or both (bilateral).
Stage I: Unilateral infrahyoid.
Stage II: Unilateral suprahyoid.
Stage III: Unilateral suprahyoid and infrahyoid.
Stage IV: Bilateral suprahyoid.
Stage V: Bilateral suprahyoid and infrahyoid.
Epidemiology
Lymphangiomas are rare, accounting for 4% of all vascular tumors in children. Although lymphangioma can become evident at any age, 50% are seen at birth, and 90% of lymphangiomas are evident by 2 years of age.Signs and symptoms
There are three distinct types of lymphangioma, each with their own symptoms. They are distinguished by the depth and the size of abnormal lymph vessels, but all involve a malformation of the lymphic system. Lymphangioma circumscriptum can be found on the skin's surface, and the other two types of lymphangiomas occur deeper under the skin.- Lymphangioma circumscriptum, a microcyticMicrocytosisMicrocytosis is a condition where red blood cells are unusually small when their mean corpuscular volume is measured.It is also known as "microcythemia".When associated with anemia, it is known as microcytic anemia....
lymphatic malformation, resembles clusters of small blisters ranging in color from pink to dark red. They are benign and do not require medical treatment, although some patients may choose to have them surgically removed for cosmetic reasons. - Cavernous lymphangiomas are generally present at birth, but may appear later in the child's life. These bulging masses occur deep under the skin, typically on the neck, tongue and lips, and vary widely in size, ranging from as small as a centimeter in diameter to several centimeters wide. In some cases, they may affect an entire extremity such as a hand or foot. Although they are usually painless, the patient may feel mild pain when pressure is exerted on the area. They come in the colors white, pink, red, blue, purple, and black; and the pain lessens the lighter the color of the bump.
- Cystic Hygroma shares many commonalities with cavernous lymphaniomas, and some doctors consider them to be too similar to merit separate categories. However, cystic lymphangiomas usually have a softer consistency than cavernous lymphaniomas, and this term is typically the one that is applied to lymphangiomas that develop in fetuses. They usually appear on the neck (75%), arm pit or groin areas. They often look like swollen bulges underneath the skin.
Causes
The direct cause of lymphangioma is a blockage of the lymphatic system as a fetusFetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
develops, although symptoms may not become visible until after the baby is born. This blockage is thought to be caused by a number of factors, including maternal alcohol use
Fetal alcohol syndrome
Fetal alcohol syndrome is a pattern of mental and physical defects that can develop in a fetus in association with high levels of alcohol consumption during pregnancy. Current research also implicates other lifestyle choices made by the prospective mother...
and viral infections during pregnancy. Why the embryonic lymph sacs remain disconnected from the rest of the lymphatic system is not known.
Cystic lymphangioma that emerges during the first two trimesters of pregnancy is associated with genetic disorders such as Noonan syndrome
Noonan syndrome
Noonan Syndrome is a relatively common autosomal dominant congenital disorder considered to be a type of dwarfism, that affects both males and females equally. It used to be referred to as the male version of Turner's syndrome ; however, the genetic causes of Noonan syndrome and Turner syndrome...
and trisomies 13
Patau syndrome
Patau syndrome, also known as trisomy 13 and trisomy D, is a chromosomal abnormality, a syndrome in which a patient has an additional chromosome 13 due to a nondisjunction of chromosomes during meiosis. Some are caused by Robertsonian translocations...
, 18
Edwards syndrome
Trisomy 18 is a genetic disorder caused by the presence of all or part of an extra 18th chromosome. It is named after John H. Edwards, who first described the syndrome in 1960...
, and 21. Chromosomal aneuploidy
Aneuploidy
Aneuploidy is an abnormal number of chromosomes, and is a type of chromosome abnormality. An extra or missing chromosome is a common cause of genetic disorders . Some cancer cells also have abnormal numbers of chromosomes. Aneuploidy occurs during cell division when the chromosomes do not separate...
such as Turner syndrome
Turner syndrome
Turner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent...
or Down syndrome
Down syndrome
Down syndrome, or Down's syndrome, trisomy 21, is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. It is named after John Langdon Down, the British physician who described the syndrome in 1866. The condition was clinically described earlier in the 19th...
were found in 40% of patients with cystic hygroma.
Pathophysiology
In 1976 Whimster studied the pathogenesisPathogenesis
The pathogenesis of a disease is the mechanism by which the disease is caused. The term can also be used to describe the origin and development of the disease and whether it is acute, chronic or recurrent...
of lymphangioma circumscriptum, finding lymphatic cisterns in the deep subcutaneous plane are separated from the normal network of lymph vessels. They communicate with the superficial lymph vesicles through vertical, dilated lymph channels. Whimster theorized the cisterns might come from a primitive lymph sac that failed to connect with the rest of the lymphatic system during embryonic development.
A thick coat of muscle fibers that cause rhythmic contractions line the sequestered primitive sacs. Rhythmic contractions increase the intramural pressure, causing dilated channels to come from the walls of the cisterns toward the skin. He suggested that the vesicles seen in lymphangioma circumscriptum are outpouchings of these dilated projecting vessels.
Lymphatic and radiographic studies support Whimsters observations. Such studies reveal that big cisterns extend deeply into the skin and beyond the clinical lesions. Lymphangiomas that are deep in the dermis show no evidence of communication with the regular lymphatics. The cause for the failure of lymph sacs to connect with the lymphatic system is not known.
Microscopically, the vesicles in lymphangioma circumscriptum are greatly dilated lymph channels that cause the papillary dermis to expand. They may be associated with acanthosis
Acanthosis
Acanthosis is diffuse epidermal hyperplasia.Acanthosis implies increased thickness of stratum spinosum. It is a disease ofthe prickle cell layer of the skin, where warts appear on the skin or inside the mouth.-References:...
and hyperkeratosis
Hyperkeratosis
Hyperkeratosis is thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin, and also usually accompanied by an increase also in the granular layer...
. There are many channels in the upper dermis which often extend to the subcutis (the deeper layer of the dermis, containing mostly fat and connective tissue). The deeper vessels have large calibers with thick walls which contain smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
. The lumen is filled with lymphatic fluid, but often contains red blood cells, lymphocytes, macrophages, and neutrophils. The channels are lined with flat endothelial cells. The interstitium has many lymphoid cells and shows evidence of fibroplasia (the formation of fibrous tissue). Nodules (A small mass of tissue or aggregation of cells) in cavernous lymphangioma are large, irregular channels in the reticular dermis and subcutaneous tissue that are lined by a single layer of endothelial cells. Also an incomplete layer of smooth muscle also lines the walls of these channels. The stroma consists of loose connective tissue with a lot of inflammatory cells. These tumors usually penetrate muscle. Cystic hygroma is indistinguishable from cavernous lymphangiomas on histology.
The typical history of Lymphangioma circumscriptum shows a small number of vesicles on the skin at birth or shortly after. In subsequent years, they tend to increase in number, and the area of skin involved continues to expand. Vesicles or other skin abnormalities may not be noticed until several years after birth. Usually, lesions are asymptomatic or do not show any evidence of a disease, but, mostly, patients may have random break outs of some bleeding and major drainage of clear fluid from ruptured vesicles.
Cavernous lymphangioma first appears during infancy, when a rubbery nodule with no skin changes becomes obvious in the face, trunk, or extremity. These lesions often grow at a rapid pace, similar to that of raised hemangioma
Hemangioma
A hemangioma of infancy is a benign self-involuting tumor of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and sometimes resolves by age 10. In more severe case hemangioma may have permanency, if not treated by a physician...
s. No family history of prior lymphangiomas is described.
Cystic hygroma
Cystic hygroma
A cystic hygroma is a congenital multiloculated lymphatic lesion that can arise anywhere, but is classically found in the left posterior triangle of the neck. This is the most common form of lymphangioma. It contains large cyst like cavities containing watery fluid.Microscopically cystic hygroma...
causes deep subcutaneous cystic swelling, usually in the axilla, base of the neck, or groin, and is typically noticed soon after birth. If the lesions are drained, they will rapidly fill back up with fluid. The lesions will grow and increase to a larger size if they are not completely removed in surgery.
Complications and concerns
This condition is associated with minor bleeding, recurrent cellulitisCellulitis
Cellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,...
, and lymph fluid leakage. Two cases of lymphangiosarcoma
Lymphangiosarcoma
Lymphangiosarcoma is a rare malignant tumor which occurs in long-standing cases of primary or secondary lymphedema. It involves either the upper or lower lymphedemateous extremities but is most common in upper extremities.-Signs and Symptoms:...
arising from lymphangioma circumscriptum
Superficial lymphatic malformation
Superficial lymphatic malformation is a congenital malformation of the superficial lymphatics, presenting as groups of deep-seated, vesicle-like papules resembling frog spawn, at birth or shortly thereafter....
have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
.
In cystic hygroma, large cysts can cause dysphagia
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis
Cytogenetics
Cytogenetics is a branch of genetics that is concerned with the study of the structure and function of the cell, especially the chromosomes. It includes routine analysis of G-Banded chromosomes, other cytogenetic banding techniques, as well as molecular cytogenetics such as fluorescent in situ...
to determine if they have chromosomal abnormalities, and parents should receive genetic counseling
Genetic counseling
Genetic counseling or traveling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning...
because this condition can recur in subsequent pregnancies.
Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma.
Treatment and prognosis
The prognosis for lymphangioma circumscriptum and cavernous lymphangioma is generally excellent. Draining lymphangiomas of fluid provides only temporary relief, so they are removed surgically.Cystic Hygroma can be treated with OK432 (Picibanil)
The least invasive and most effective form of treatment is now performed by interventional radiologists. A sclerosing agent, such as 1% or 3% sodium tetradecyl sulfate, doxycycline, or ethanol, may be directly injected injected into a lymphocele. "All sclerosing agents are thought to work by ablating the endothelial cells of the disrupted lymphatics feeding into the lymphocele."
Lymphangioma circumscription can be healed when treated with a flashlamp pulsed dye laser
Dye laser
A dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and...
, although this can cause port-wine stains and other vascular lesions.
Treatment for cystic hygroma involves the removal of the abnormal tissue; however complete removal may be impossible without removing other normal areas. Surgical removal of the tumor is the typical treatment provided, with the understanding that additional removal procedures will most likely be required as the lymphangioma grows. Most patients need at least two procedures done for the removal process to be achieved. Recurrence is possible but unlikely for those lesions able to be removed completely via excisional surgery. Radiotherapy and chemical cauteries are not as effective with the lymphangioma than they are with the hemangioma
Hemangioma
A hemangioma of infancy is a benign self-involuting tumor of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and sometimes resolves by age 10. In more severe case hemangioma may have permanency, if not treated by a physician...
.
Diagnosis
Cases of lymphangioma are diagnosed by histopathologicHistopathology
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...
inspection. In prenatal cases, cystic lymphangioma is diagnosed using an ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
; when confirmed amniocentesis
Amniocentesis
Amniocentesis is a medical procedure used in prenatal diagnosis of chromosomal abnormalities and fetal infections, in which a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for...
may be recommended to check for associated genetic disorders.
History
In 1828, Redenbacher first described a lymphangioma lesion. In 1843, Wernher gave the first case report of a cystic hygroma, from the GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
"hygroth" meaning fluid and "oma" meaning tumor. In 1965, Bill and Summer proposed that cystic hygromas and lymphangiomas are variations of a single entity and that its location determines its classification.
External links
- USC
- Lymphatic Research Foundation: {http://www.lymphaticresearch.org/main.php?content=home}