Lymphangioma

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Lymphangioma is a lymphatic malformation, a benign proliferation of lymph vessels, forming a yellowish tumor on the skin, composed of a mass of dilated lymph vessels. It is often removed by a form of surgery using an electric current electrocoagulation for cosmetic reasons. It is rare, incidence being estimated at around one per 10,000 live births. Lymphangiomas are fluid-filled sacs resulting from blockage of the lymphatic system, and are often associated with karyotype abnormalities such as Turner syndrome.

These tumors may occur anywhere, but around 75% occur in the head and neck regions, with a predilection for the left side. Most (around 90%) are either evident at birth or become evident before age two years. The three types of lymphangioma are Cystic lymphangioma (or Cystic Hygroma), Lymphangioma cavernosum, and Lymphangioma circumscriptum. The tumor is a hamartoma, or vascular developmental abnormality arising from lymphatic vessels, appearing as a raised, soft, shaggy, bubbly, pinkish-white lesion; cosmetic considerations may warrant attempted removal of lymphangiomas.

Types of Lymphangioma

• Lymphangioma circumscriptum - Also referred to as cutaneous this is a type of birthmark that generally occurs in clusters. They look a lot like small blisters and range in color from pink to dark red. They are benign and do not really require any medical treatment. For cosmetic reasons, some patients may choose to have them surgically removed. Lymphangiomas Simplex is often included in this type of Lymphangioma. This is also a type of tumor that is commonly seen in younger children. ^[1]
• Cavernous lymphangioma - This is an uncommon form generally arising during infancy. This occurs deep under the skin and the external skin is not involved. Because they are deep seated, they form a bulging mass, that is usually painless. This is also a tumor filled with lymph that is often mixed with blood. It usually affects the tongue and lips.^[2]
• Cystic Hygroma - These are soft lymph filled masses within a thin-walled "sac" generally appearing on the neck (75%), arm pit or groin areas. They often look like a swollen bulges underneath the skin. While they are generally present at birth, children up to three years old may experience them. There is also disagreement on whether this type is distinctly different enough from cavernous lymphangioma to be classified separately.

Lymph nodes

One of many small oval structures that filter the lymph, fight infection and in which there are formed white blood cells and blood plasma cells. They come in various sizes, they can range from being as small as a pin head or as big as a bean. Each node is enclosed in a fibrous capsule and consist of closely packed white cells(lymphocytes) connected tissue and lymph path ways. Most lymph nodes are clustered in certain areas, such as mouth, neck, lower armpit and groin. For example visceral lymph nodes filter lymph circulating in the lymphatic vessels of the viscera of the chest, lower body and pelvis. The lymphatic network and nodes of the breast are especially crucial in the diagnosis and treatment of breast cancer in women also called lymph gland.

A Lymph

is a clear, watery, sometimes faintly yellowish fluid derived from body tissues that contains white blood cells and circulates throughout the lymphatic system, returning to the venous bloodstream through the thoracic duct. Lymph acts to remove bacteria and certain proteins from the tissues, transport fat from the small intestine, and supply mature lymphocytes to the blood.^[3]

A Lymph Gland

is any of the small bodies located along the lymphatic vessels, particularly at the neck, armpit, and groin, that filter bacteria and foreign particles from lymph fluid. During infection, lymph nodes may become swollen with activated lymphocytes.

A Lymphatic Vessel

is any of the vascular channels that transport lymph throughout the lymphatic system and freely anastomose with one another.^[4]

Complications and concerns

Lymphangioma circumscriptum may occur. This condition is associated with minor bleeding, recurrent cellulitis, and lymph fluid leakage. Two cases of lymphangiosarcoma arising from lymphangioma circumscriptum have been reported. Both patients were exposed to an x-ray therapy.It did not help the patients and caused difficulties so radiation therapy should be avoided in lymphangiomas. In cystic hygroma, large cysts can cause dysphagia, respiratory problems, and serious infection if they involve the neck. Cystic hygroma can be associated with the following congenital disorders: Turner syndrome Chromosomal aneuploidy Hydrops fetalis Down syndrome and other disorders Fetal alcohol syndrome Noonan syndrome Several other congenital syndromes Patients with cystic hygroma should go through cytogenetic analysis for chromosomal aneuploidy. Parents should get genetic counseling because this abnormality can recur in any other pregnancies that the mother may have.^[5] Complications that may happen after cystic hygroma is removed are:Bleeding,Damage to structures in the neck caused by surgery,infection,and return of the cystic hygroma.^[6]

Causes

The reason that these embryonic lymph sacs remain disconnected from the rest of the lymphatic system is not known.^[7] Cystic Hygroma is a birth defect.It occurs as the baby grows in the womb from pieces of material that carry fluid and white blood cells. This material is called embryonic lymphatic tissue.After the child is born,cystic hygroma usually looks like a soft bulge under the skin. Sometimes the cyst is not noticeable right after the birth, it may appear later on in the child's life.^[8]

Histologic findings

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.^[9]

Treatment and prognosis

Lymphangioma Circumscription is usually successfully healed when treated with a flashlamp pulsed dye laser. This can cause port-wine stains and other vascular lesions.^[10] Because of the nonencapsulated and "infiltrating" nature of the lymphangioma, complete removal is often not advised and 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 child and possibly 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.^[11] The treatment for cystic hygroma involves the removal of the abnormal tissue. This can be complicated because this tissue may have invaded other parts in the neck or area where it is found making the procedure almost impossible.Some treatments have been used but only with limited success:chemotherapy medications,injection of sclerosing medications,radiation therapy,and steroids.When cystic hygroma is removed it is most likely to return.^[12]

Pathophysiology

In 1976 Whimster studied the pathogenesis of lymphangioma circumscriptum. Whimster said,that the basic pathologic process is the collection of lymphatic cisterns(a receptacle for holding water or other liquid) in the deep subcutaneous plane. These cisterns are separated from the normal network of lymph vessels, but they communicate with the superficial lymph vesicles through vertical, dilated lymph channels. Whimster thought that the cisterns might come from a primitive lymph sac that doesn't connect with the rest of the lymphatic system during its 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.^[2]

History

Lymphangioma circumscriptum The typical history shows a small number of vesicles on the skin at birth or shortly after. As the years go on, they usually increase in number, and the area of skin that it takes over will begin to increase also.Some vesicles and 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 Usually, during infancy, a rubbery nodule with no skin changes becomes obvious in a single location, such as the face, trunk, or extremity. These lesions often grow at a rapid pace, similar to that of raised hemangiomas.No family history of prior lymphangiomas is described. Cystic hygroma Soon after birth, the infant is noted to have a deep subcutaneous cystic swelling, usually in the axilla, base of the neck, or groin. If the lesions are drained, they will quickly fill back up with fluid.The lesions will grow and increase to a larger size if they are not completely removed in surgery.^[2]

Epidemiology

Lymphangiomas are rare, they account for 4% of all vascular tumors and approximately 25% of all benign vascular tumors in children.There is no sign of racial predominance.Also equal sex incidences are reported in most studies. Some groups have reported though that lymphangioma circumscriptum is more common in females than in males, while some report a 3:1 male-to-female ratio.Lymphangioma can become evident at any age, but the often occurs at birth or in the early stages of life. About 50% of lymphangiomas are seen at birth, and most lymphangiomas are evident by the time the patient is 5 years of age.^[13]

References

External links

• USC
• Cystic Hygroma at eMedicine
• Lymphatic Research Foundation: {http://www.lymphaticresearch.org/main.php?content=home}