Quick Review for Patients
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The lymphangioma is a benign hamartomatous hyperplasia of lymphatic vessels, with three-fourths of all cases occurring in the head and neck region. While occasional adult-onset cases occur, this tumor is thought to be a developmental malformation of vessels which have poor communication with the normal lymph system. Very large cystic spaces may be seen in lesions proliferating in loose connective tissues and fascial spaces. Diagnosed cases are typically superficial but may extend deeply into underlying connective tissues. Rarely, multiple lesions are seen in infancy and childhood in lymphangiomatosis, the lymphatic counterpart to angiomatosis of blood vessels and a potentially life-threatening disease when visceral involvement occurs.
Oral mucosal lymphangioma almost always becomes apparent prior to the third year of life; half of all cases are congenital. There is no gender predilection. Oral lesions are most frequently found on the tongue, where they may produce considerable macroglossia and dysfunction (Figures 1-3). Any oral or pharyngeal site may, however, be affected and the most common head and neck location is the lateral neck, where this lesion typically contains large cystic spaces and is commonly called cystic lymphangioma or cystic hygroma, discussed elsewhere in the present text.
The cervical lymphangioma occurs most frequently in the posterior triangle, but lesions of the anterior triangle tend to be more problematic, interfering with the patientís ability to breath or swallow and extending upward into the oral cavity, or downward into the mediastinum (Figure 4). Torticollis or wry neck may develop from cervical involvement and cervical lesions tend to be much larger than oral or pharyngeal lesions, sometimes larger than the patientís head at birth.
Superficial oral mucosal lymphangiomas often demonstrate a pebbled or botryoid appearance, once referred to as chronic "clustered blisters" because of the translucent appearance of the lymphatic channels, which may have only sparse fibrovascular tissue separating their endothelial walls from the surface epithelium. Secondary hemorrhage into the lymphatic vessels may cause some of the surface "vesicles" to appear red or blue. Satellite lesions several millimeters from the main lesional mass may be seen.
Occasional lesions show only widely scattered clear "vesicles" interspersed with blood-filled papules or blebs. Such lesions are, presumably, a combination of lymphangioma and hemangioma, and are termed hemangiolymphangioma. They behave more like lymphatic than vascular tumors.
A unique congenital alveolar lymphangioma is seen on the alveolar mucosa of African-American neonates. This lesion is seldom greater than a centimeter in size and is often bilateral on the alveolar ridge (Figure 5). The mandible is more often affected than the maxilla and the lesion typically disappears during the months after birth.
Deeper lymphangiomas present with an irregular surface nodularity and are quite soft and painless. They may feel like a "ball of worms" on palpation, but are usually rather nonspecific and ill-defined.
Pathology and Differential Diagnosis
The lymphangioma consists of multiple, intertwining lymph vessels in a loose fibrovascular stroma, sometimes with scattered aggregates of lymphoid tissue. The lymphatic vessels of a lymphangioma are lined by a single layer of endothelial cells with flattened, occasionally plump, nuclei (Figures 6-8).
The vessels may be capillary in size, with a very attenuated lumen or may be so dilated that the cystic areas can be visualized at surgery. Oral examples are more likely to contain the dilated vessels. The vessels are filled with a uniform, eosinophilic, proteinaceous fluid with occasional erythrocytes and leukocytes. Those vessels just beneath the surface epithelium tend to fill or replace the connective tissue papillae, perhaps producing a papillary surface change. It is not unusual for a superficial lesion to have little or no fibrous stroma separating it from the overlying epithelium.
There is no encapsulation of lymphatic vessels, even with the tumors which appear well circumscribed clinically. Deeper lesions show vessels interspersed between adipocytes and striated muscle bundles. Deeper lesions also tend toward greater vessel dilation.
Some authorities prefer to subclassify lymphangioma into four categories:
These categories are somewhat artificial and many lesions are combinations of categories. Microscopic features of cystic hygroma are discussed elsewhere in the present text. Occasional lesions demonstrate proliferation of lymphatic channels with another connective tissue component, primarily smooth muscle cells (lymphangiomyoma).
The lymphatic endothelial cells in these or more routine lymphangiomas can be identified via positive immunoreactivity with factor VIII-associated antigen and CD31, as well as positive staining with Ulex europaeus. Immunohistochemistry is not a particularly reliable means of distinguishing lymphangioma from hemangioma, but this is not usually a problem because of the large number of erythrocytes in the vessels of the latter.
In addition to distinguishing lymphangioma from hemangioma, the pathologist must also delineate it from well-differentiated angiosarcoma and patch-stage Kaposiís sarcoma. Recently, a lymphangioma-like variant of Kaposiís sarcoma has been reported.
Treatment and Prognosis
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.
References (Chronologic Order)
Note: General references can be found by clicking on that topic to the left.
Levin LS, Jorgenson RJ, Jarvey BA. Lymphangiomas of the alveolar ridges in neonates. Pediatrics 1976; 58:881-884.
Goldberg MH, Nemarich AN, Danielson P. Lymphangioma of the tongue: medical and surgical therapy. J Oral Maxillofac Surg 1977; 35:841-844.
Wilson S, Gould AR, Wolff C. Multiple lymphangiomas of the alveolar ridge in a neonate: case study. Pediatr Dent 1986; 8:231-234.
Kennedy TL. Cystic hygroma-lymphangioma: a rare and still unclear entity. Laryngoscope 1989; 99:1-10.
Ricciardelli EJ, Richardson MA. Cervicofacial cystic hygroma: patterns of recurrence and management of the difficult case. Arch Otolaryngol Head Neck Surg 1991; 117:546-553.
Ramani P, Shah A. Lymphangiomatosis: histologic and immunohistochemical analysis of four cases. Am J Surg Pathol 1993; 17:329-335.
Herron GS, Rouse RV, Kosek JC, et al. Benign lymphangioendothelioma. J Am Acad Dermatol 1994; 31:362-368.
Cossu S, Satta R, Cottoni F, Massarelli G. Lymphangioma-like variant of Kaposiís sarcoma Ė clinicopathological study of 7 cases with review of the literature. Am J Dermatopathol 1997; 19:16-22.
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