Lymphatic malformations

Lymphangioma, is a lymphatic malformation, a benign proliferation of lymph vessels, or a yellow-ish tumor on the skin, composed of a mass of dilated lymph vessels. It is often removed by surgery or a form of surgery using an electric currentelectrocoagulation for cosmetic reasons. It is rare, incidence estimated to be around 1 per 10 000 live births. They are fluid filled sacs that result from blockage of the lymphatic system. They are often associated with karyotype abnormalities such as Turner syndrome. These tumors may occur anywhere but usually occur in the head and neck (75%), with a predilection for the left side. Most (90%) are either evident at birth or become evident before age 2 years. Other types of Lymphangioma are Cystic lymphangioma, Lymphangioma cavernosum and Lymphangioma circumscriptum. The tumor is a hamartoma or vascular developmental abnormality arising from lymphatic vessels, manifesting 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 "kind" of birthmark generally occurring in clusters. They resemble small blisters and range in color from pink to dark red. They are benign and usually require no medical treatment. For cosmetic reasons, some patients may choose to have them surgically removed. Lymphangiomas Simplex is often included in this type.This is also a type of tumor that is commonly seen in younger children. Cavernous lymphangioma - This is an uncommon form generally arising during infancy. These are deep seated underneath the dermis and the external skin is not involved. Because they are deep seated, they form a bulging mass, painless mass. This is also a tumor filled with lymph that is often mixed with blood. It usually affects the tongue and lips. 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 usually present a swollen bulges underneath the skin. While they 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.

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.

Complications&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. However, in both of the patients, the preexisting lesion was exposed to extensive x-ray therapy. Therefore, 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 trisomy disorders Fetal alcohol syndrome Noonan syndrome Several other congenital syndromes Patients with cystic hygroma should undergo cytogenetic analysis for chromosomal aneuploidy. Parents should receive genetic counseling because aneuploidic conditions can recur in subsequent pregnancies.

Causes

The reason that these embryonic lymph sacs remain disconnected from the rest of the lymphatic system is not known.

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. These channels are numerous in the upper dermis and often extend to the subcutis. These deeper vessels seem to have a large caliber, and they often have a thick wall that contains smooth muscle. The lumen is filled with lymphatic fluid, but it often contains red blood cells, lymphocytes, macrophages, and neutrophils. These channels are lined by flat endothelial cells, which stain positive for Ulex europaeus agglutinin-I. The interstitium often has numerous lymphoid cells and shows evidence of fibroplasia.Nodules in cavernous lymphangioma are characterized by large, irregular channels in the reticular dermis and subcutaneous tissue that are lined by a single layer of endothelial cells. An incomplete layer of smooth muscle often lines the walls of these malformed channels. The surrounding stroma consists of loose or fibrotic connective tissue with a number of inflammatory cells. These tumors often penetrate muscle.Cystic hygroma is indistinguishable from cavernous lymphangiomas on histology.

Treatment & 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. Because of the nonencapsulated and "infiltrating" nature of the lymphangioma, complete removal is often inadvisable and may be impossible without excessive removal of surrounding normal structures. Surgical debulking of the tumor is, therefore, the typical treatment provided, with the understanding that additional debulking procedures will most likely be required as the affected child grows. Most patients will need two to four procedures before full growth and development have been achieved. Recurrence is possible but unlikely for those lesions able to be removed completely via excisional surgery. Radiotherapy and chemical cauteries are much less effective with the lymphangioma than they are with the hemangioma.

Pathophysiology

In 1976 Whimster studied the pathogenesis of lymphangioma circumscriptum. Whimster said, the basic pathologic process is the collection of lymphatic cisterns 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 these cisterns might arise from a primitive lymph sac that fails to connect with the rest of the lymphatic system during its embryonic development. A thick coat of muscle fibers that cause rhythmic contractions line these sequestered primitive sacs. Rhythmic contractions increase the intramural pressure, causing dilated channels to protrude 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. Whimster's observations are supported by those of lymphangiographic and radiographic studies. These studies revealed that large multilobulated cisterns extend deep in the dermis and laterally beyond the obvious clinical lesions. These deep lymphangiomas show no evidence of communication with the adjacent normal lymphatics. The cause for the failure of these primitive lymph sacs to connect to the rest of the lymphatic system is not known.A thick coat of muscle fibers that cause rhythmic contractions line these sequestered primitive sacs. Rhythmic contractions increase the intramural pressure, causing dilated channels to protrude 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.

History

Lymphangioma circumscriptum The typical history involves 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, but, occasionally, patients may have spontaneous episodes of minor bleeding and copious drainage of clear fluid from ruptured vesicles. Cavernous lymphangioma Typically, during infancy, a solitary rubbery nodule with no skin changes becomes evident in a single location, such as the face, trunk, or extremity. These lesions often have a fast growth phase 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 these lesions are drained, they tend to fill up rapidly with lymph fluid. The lesions tend to grow and increase to a large size if they are not completely excised at surgery.

Facts

Lymphangiomas are rare. They account for 4% of all vascular tumors and approximately 25% of all benign vascular tumors in children. No racial predominance is reported. Equal sex incidences are reported in most studies. Some groups have reported that lymphangioma circumscriptum is more common in females than in males, while others report a 3:1 male-to-female ratio. Lymphangioma can become evident at any age, but the greatest incidence occurs at birth or early in life. About 50% of lymphangiomas are seen at birth, and most lymphangiomas are evident by the time the patient is aged 5 years.

External links

• USC
• Cystic Hygroma at eMedicine