Oral Lymphangiomas

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Lymphangiomas and cystic hygromas are rare benign hamartomatous lesions of the lymphatic system. Determining the true incidence of these lesions is difficult because uniformity in classification and nomenclature is lacking. Moreover, lymphatic malformations are generally treated in tertiary and quaternary medical centers, distorting any view of their true incidence.

These lesions, more correctly referred to as lymphatic malformations, have a marked predilection for the head and neck, with as many as 75% presenting therein. No clear sex predilection is demonstrated, and whites appear to be affected more often than people of other races.

Of lymphatic malformations, 50% are present at birth, and 90% are diagnosed by the time the individual is aged 2 years. However, the time of diagnosis can range from 19 weeks’ gestation to the individual’s second decade of life.

Of lymphatic malformations in the oral cavity, 40-50% involve the tongue, which is the preferred site of intraoral involvement. The buccal mucosa is the second most common. These distinctions can be somewhat artificial because lesions that involve the oral cavity may extend from the orbits to the upper mediastinum and axillae.

Lymphatic malformations are typically classified as simple microcystic, simple macrocystic, or mixed microcystic and macrocystic lesions, according to their predominant histologic features.

        

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Pathophysiology
Although no clear consensus on the mechanism for lesion development exists, the lesions likely develop as a result of aberrant sequestration of portions of the primitive embryonic anlagen. The sequestered areas never achieve efficient anastomoses with the larger lymph channels and, as a result, they consist of little more than functionally blocked lymphatic tracts. This blockage may result in increased hydrostatic pressure with subsequent expansion of the lesion until a pressure equilibrium is achieved with the surrounding tissues. The importance of the surrounding tissues in determining the nature of the lesion is evident, as microcystic lesions are more common in the tongue, whereas macrocystic lesions predominate in the relatively compliant tissues of the neck.

At the molecular level, some have hypothesized overexpression of growth factors or their associated receptors essential to lymphatic development. Two examples would be vascular endothelial growth factor types 3 and C.

A neoplasm is classically defined as an abnormal mass of tissue. Its growth exceeds and is uncoordinated with that of healthy tissues and persists in an excessive manner after the inciting stimuli is removed. In contrast, lymphatic malformations and/or lymphangiomas tend to grow commensurately with the child’s growth and rarely regress spontaneously. Rapid enlargement of the lesions (out of proportion with the surrounding tissues) is observed only in conjunction with infections of the upper respiratory tract or the lesion itself or with trauma and hemorrhage into the malformation. In addition, the lesions have a typical endothelial cell cycle.

For these reasons, lymphangiomas are considered to be malformations rather than neoplasms. In a teleologic sense, this determination remains rather unsatisfying because the predisposing event (ie, the sequestration of embryonic anlagen) occurs long before these lesions develop. As previously stated, only 50% of the lesions are diagnosed at birth, and a few reports of lesions developing in early adulthood exist.

Moreover, at prenatal ultrasonography, fetal lymphatic malformations are observed to develop and occasionally resolve in utero. Some unrecognized event must be superimposed on these earlier events resulting in the development of a clinically apparent lesion. These events are apparently reversible because the lesions occasionally spontaneously regress in fetuses and children. The inciting event must then be occurring during the maturation of the formed lymphatic systems.

        

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Differential Diagnosis

Branchial Cleft Cyst
Cellulitis
Cheilitis Granulomatosa (Miescher-Melkersson-Rosenthal Syndrome)
Dermoid Cyst
Infantile Hemangioma
Lymphangioma
Mucocele and Ranula
Oral Hemangiomas

Medical Care
No appropriate medical care is available for oral lymphatic malformations, other than observation in selected patients. For example, a child with a superficial lesion without untoward functional sequelae may be observed. In all patients, address the perioperative airway, speech, and nutritional concerns.

Observation
Some authors advocate a period of watchful waiting in cases of asymptomatic lesions because a few reports show that the lesions regress spontaneously.
Other authors recommend excision as soon as the patient can safely tolerate a general anesthetic. These authors are concerned about the complications associated with untreated lesions and recognize the fact that repeated infections make future excision difficult.
Radiation therapy
Radiation therapy is of only historical interest.
This treatment should not be used because of its poor effectiveness, its multiple complications, and the risk of postradiation malignancies.
Surgical Care
Treatment of lymphatic malformations continues to evolve. Although surgical removal is overwhelmingly the most common modality used, sclerotherapy is being increasingly used to treat macrocystic lesions throughout the head and neck. Often the 2 modalities are combined for optimal outcomes. Determine the timing of intervention on a case-by-case basis. Lesions that impinge on the airway usually require the earliest intervention.

Isolated superficial malformations are often more of a nuisance than a debilitating condition. Given the fact that these are malformations and not true neoplasms and that they are entirely devoid of malignant potential, treatment should be aimed at maximizing the patient’s function. In addition, treatment that results in a loss of function should not be tolerated. Early involvement of consultants can be helpful in meeting the goal of maximizing the patient’s function and determining an optimal treatment plan.

Incision and drainage
Limit incision and drainage to emergent decompression of a lesion.
This procedure does not eliminate the lesion but decreases the risk of infection.
Surgical excision
Surgical excision remains the standard for treatment of lymphatic malformations, although many lesions are especially difficult to remove entirely because of their involvement with important neural and muscular structures; thus, these lesions are associated with the highest risk of recurrence and complications.
Recurrence rates of 20-40% are typically reported after surgical excision when the surgeon believes that the lesion is removed in its entirety.[6]
Complications of surgical excision of suprahyoid and oral lesions are also common. These operations can be difficult undertakings because of the diffuse infiltrative nature of the lesions and the difficulty in determining normal tissue from abnormal tissue.
Complication rates typically are 20-30%. Complications include airway obstruction, seromas and hematomas, infections, and cranial nerve palsies. Moreover, the reported operative mortality rates are 2.5-11.4%.
Surgical debulking, as part of a staged intervention plan, may be useful with large lingual malformations. Surgical debulking may obviate long-term tracheostomy, facilitate feeding, improve speech, and simplify further treatment, regardless of the modality used.
Surgical excision of macrocystic lesions may be facilitated by instilling fibrin glue into the cysts after partial aspiration of cystic contents.
Laser therapy
Surface laser photocoagulation is used as an adjunct for controlling the size of the tongue, treating superficial lesions, and controlling bleeding.
Good results are reported. With the exception of isolated superficial lesions, surface laser photocoagulation does not lead to a cure.
Repeated hospital admissions for laser photocoagulation are not unusual. Some patients undergo as many as 25 procedures, which can be a significant burden on the patient and his or her family. This consideration is important because the patient is already consulting with multiple specialists and undergoing multiple procedures.
Results appear to be equivalent regardless of whether carbon dioxide, argon, or Nd:YAG lasers are used.
Orthognathic surgery
Maxillofacial skeletal deformities and malocclusions should be treated with combined orthognathic and osteoplastic surgical procedures. Lesions of the upper part of the neck and, particularly, the floor of the mouth tend to be associated with bony overgrowth leading to class III malocclusions and open bite deformities. These lesions usually require combined surgical and orthodontic correction.
Orthognathic surgery is usually delayed until growth is complete, except in patients in whom the severity of the deformity necessitates earlier intervention.
Sclerotherapy[7, 8]
Myriad agents are used as sclerosing agents in attempts to avoid surgery and its attendant problems or to treat remnant lesions after partial excision.
The use of bleomycin has produced some impressive results. Good or excellent results (ie, tumor disappeared and did not recur with 3-8 injections or fewer, respectively) occur in 75-100% of patients, depending on the dominant histologic pattern of the lesion. Pulmonary fibrosis (the worst complication) generally occurs only when cumulative doses exceed 450 mg. The 50-mg doses used in this therapy have not resulted in pulmonary fibrosis. Adverse effects include fever and anorexia lasting 24 hours in about 10% of patients. No adverse effects on growth and development are reported.
Tissucol, a fibrin sealant, is reported to induce a high rate of remission in lymphatic malformations. Adverse effects are not observed, though a potential for infectious disease transmission exists. Even superficial lesions can be successfully treated, although multiple injections (as many as 3) are often required.
Ethibloc, a synthetic sclerosing agent, has been used to induce lesion regression. The complete regression rate is 60%, with minimal complications.
OK-432, a lyophilized incubation mixture of group A Streptococcus pyogenes of human origin treated with penicillin G, has been in sclerotherapy since the mid-1980s. Total or marked shrinkage is observed in 67% of lesions. OK-432 stimulates an intense inflammatory response that causes cystic spaces to shrink and preserves the endothelium with no scar formation. OK-432 may enhance the permeability of the endothelium, facilitating decompression. Adverse effects include a transient fever for 2-3 days after the injection and irritation at the injection site.
Repeated injections of sclerosing agents are often required, and resolution usually occurs over 1-4 months.
Macrocystic lesions are most amenable to sclerotherapy, followed by microcystic lesions and then superficial lesions.
Sclerotherapy does not represent an advantage compared with surgical ablation, with respect to success and ease of treatment. Success rates vary considerably depending on the agent used. Generally, boiling water, sodium morrhuate, tetracycline, 50% dextrose, and steroids are not effective in treating lymphatic malformations.
The encouraging results reported with sclerotherapy in conjunction with its low complication rate favor its adoption into the treatment protocols for lymphatic malformation, either as a stand-alone modality or as an adjunct to surgery.
Consultations
Anesthesiologist: Preoperative consultation with an anesthesiologist is often necessary for planning perioperative airway management.
Speech pathologist
Preoperative assessment by a speech pathologist can help in identifying patients with deranged swallowing mechanics and in optimizing speech patterns.
The speech pathologist’s input can help determine the need for and timing of intervention.
Postoperative consultation is often necessary for correcting any accumulated speech pathology and for managing rehabilitation, which is particularly important when lesions involve the tongue and soft palate.
Early involvement of speech pathologists and audiologists can help in identifying problems early in the course of the disease. These specialists can aid in optimizing the patient’s treatment plan.
Pediatric dentist and orthodontist
Consultation is warranted to optimize the health and development of the patient’s dentition.
Consultation with an orthodontist is warranted when orthognathic surgery is planned for the correction of maxillofacial skeletal deformities.
Pediatric dentists should be involved early in the care of children with oral lymphangiomas. Regular dental prophylaxis (q4-6mo) should be aggressively pursued to minimize the likelihood of developing an odontogenic source for infection of the malformation.
Dietitian
Dietitians should address the perioperative feeding of the patient before surgery is performed.
A dietitian can help in educating the patient and his or her family.
Otolaryngologist and/or audiologist
Otolaryngologists are instrumental in the assessment and management of lesions involving the lower airway. Tracheostomy is required in as many as 50% of infants with cervicofacial lymphatic malformations. Tracheostomy places a tremendous burden on the child and family and, significantly, negatively impairs the child’s quality of life. Decannulation should be aggressively pursued as part of the multidisciplinary management of the lesion.
When lesions involve the soft palate, the potential for eustachian tube dysfunction exists.
Because consultants may identify hearing deficits that could result, they aid in determining the need for and timing of intervention.
Diet
Depending on the location and size of the lesion, a variety of enteral feeding modalities may be required.

Short-term bypass feeding while convalescing from surgery is most easily accomplished by using a nasogastric feeding tube.
When prolonged (>4-6 wk) feeding difficulties are anticipated, a feeding gastrostomy is typically preferred.
When an oral diet is permitted, patients typically begin with a clear liquid diet until approximately 2 weeks after surgery or longer if complications delay wound healing.
Activity
Activity restrictions depend on the extent of the lesion.

Patients in whom only superficial lesions are removed do not require activity restriction.
Patients undergoing major debulking of larger lesions are generally advised to refrain from strenuous activity for approximately 4-6 weeks.

        

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