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1. Essentials of Diagnosis
• Incorrectly known as cystic hygroma or lymphangioma
The commonly used term lymphangioma implies cellular proliferation, which is incorrect. The tissue structure of these lesions, like all vascular malformations, demonstrates no proliferative component. In the simplest terms, lymphatic malformations and all vascular malformations are birth defects.
Fifty to sixty percent of lymphatic malformations are recognized at birth; 90% are recognized by the second year. Eighty percent of all lymphatic malformations are located in the head and neck. There is no gender predilection. A lymphatic malformation tends to be slowly progressive, growing with the child. In some instances, it is apparent that the lymphatic malformation rapidly increases in size. In these cases, it is likely that the lesion has either hemorrhaged into itself or has become infected. There are reports of spontaneous regression, although they are far from typical. With adequate follow-up, a regression is usually followed by a recurrence. The incidence of lymphatic malformations is unknown.
Lymphatic malformations are thought to arise from sequestrations of the developing lymphatic system.
4. Clinical Findings
An MRI scan with contrast is the typical and best means for evaluating patients with a presumed lymphatic malformation. A lymphatic malformation is hyperintense on a T2-weighted image and has only a slight increase in intensity on a T1-weighted image. A lymphatic malformation does not enhance on gadolinium contrast images. Based on the radiographic appearance of the size of the lymphatic spaces located within the lesion, lymphatic malformations are then broadly categorized as either macrocystic or microcystic. Further categorization may then be made based on the location of the lesion
This type of staging system does offer some important prognostic information: generally, as the stage increases, the prognosis for the cure decreases. It is also generally true that facial and oropharyngeal involvement are associated with a poor prognosis. While the lymphatic malformations classification system is helpful prognostically, the staging system does not simplify the clinical complexities of dealing with children who have lymphatic malformations. A more practical classification designates these malformations as either localized and macrocystic , or diffuse and interdigitating . The therapeutic goals and appropriate treatments for the two groups are dramatically different.
The increased use of prenatal ultrasound has led to the diagnosis of patients with lymphatic malformations in utero, which has led to some treatment dilemmas at very early stages of life. Not all fetal ultrasound diagnoses of cystic hygroma equate with the postnatal condition of lymphatic malformation. Posterior nuchal swellings are often referred to as cystic hygromas on ultrasonography. This finding is associated with chromosomal abnormalities and increased fetal death rates. These posterior nuchal swellings are not necessarily associated with lymphatic malformation.
5. Differential Diagnosis
When these lesions become infected or hemorrhage into themselves, their rapid enlargement can be misdiagnosed as an infected branchial cyst or acute lymphadenitis. A plunging ranula or a branchial cyst can be confused with a lymphatic malformation. Aspiration and examination of the cyst fluid should differentiate these lesions.
Diffuse microcystic cervicofacial disease often results in mandibulomaxillary hypertrophy, which is due to the direct invasion of the bone and growth of the lymphatic malformation within the bone. After the child has matured, this hypertrophy can be managed with mandibular osteotomy and, if necessary, Le Fort osteotomies.
A secure airway is essential in patients with diffuse microcystic cervicofacial disease. It is often necessary to perform a tracheostomy to avoid acute respiratory problems. A lymphatic malformation often swells with the onset of a general viral infection or a remote bacterial infection. This swelling typically resolves with the resolution of the infection. Occasionally, the malformation itself will become infected, which generally requires IV antibiotics.
Multiple treatments have been employed for the management of the lesions, which indicates that none have been completely effective. It is helpful to consider treatment of the localized and diffuse groups separately.
I. Localized Malformations
The treatment of localized malformations relies essentially on sclerosis or surgery, except in some specialized locations. Both surgery and sclerosis are very effective for localized lesions; choosing between these two modalities depends on the surgeon’s experience and the specifics of the patient’s situation.
1. Sclerosis - Numerous agents have been used in an effort to sclerose these lesions, including boiling water, tetracycline, cyclophosphamide, sodium tetradecyl sulfate, bleomycin,doxycycline, alcohol, and OK-432. OK-432 is a medication developed in Japan with extensive worldwide use. In the United States, the medication is under FDA investigation. The medication, a streptococcus culture treated and killed with penicillin, incites an immune response (delayed hypersensitivity reaction) in the location of the lymphatic malformation. Typically, the lesion swells and subsequently resolves, although it may be necessary to inject the medication several times for some lesions.
3. Tongue reduction surgery - The tongue can also become massively enlarged due to lymphatic malformation . Children with this condition cannot be managed with laser and generally require tongue reduction surgery.
4. CO2 laser surgery - Glottic involvement is best managed with a CO2 laser to open lesions and debulk airway obstruction. A tracheostomy tube should always be in place for this type of airway surgery.
II. Diffuse Malformations
Berenguer B, Burrows PE, Zurakowski D, Mulliken JB. Sclerotherapy of craniofacial venous malformations: complications and results. Plast Reconstr Surg. 1999;104:111. [PMID: 10597669] (A review of a large study with detailed descriptions of techniques.)
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