Oral Lymphangiomas Workup

Approximately 40% of lesions are diagnosed on the basis of their clinical appearance alone; however, this observation does not obviate further imaging. Imaging plays several roles in the evaluation and treatment of oral lymphatic malformations. Imaging helps in determining the extent of the lesion and its proximity to vital structures, in determining whether the lesion contains a vascular component, and is used to assess recurrence in treated lesions.

• Ultrasonography

  • Prenatal ultrasonography can be used to identify fetal cystic hygromas. A diagnosis of fetal cystic hygroma has important ramifications for the fetus because this lesion is often associated with major chromosomal abnormalities. However, caution is warranted with such a diagnosis because these lesions are known to regress in utero. In addition, the prenatal diagnosis of fetal cystic hygroma has an error rate as high as 70%, depending on the time of diagnosis.
  • Ultrasonography may be an invaluable tool for monitoring a lesion for regression or recurrence. Lesions will appear cystic on ultrasound, with little evidence of flow upon Doppler interrogation.
• MRI^[5]

  • Contrast-enhanced MRI is the most useful imaging modality for the assessment of lymphatic malformations.
  • The superior soft-tissue definition is critical in planning surgery and determining the extent of the lesion.
  • MRI is particularly important in distinguishing vascular malformations or mixed lesions from lymphatic malformations. Both vascular and lymphatic variants have a low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. However, in contrast to vascular malformations, lymphatic variants fail to enhance after the administration of contrast material.
  • Fetal MRI is an excellent diagnostic tool for further evaluation of oral and anterior cervical lesions detected on prenatal ultrasound. It can be invaluable in determining the potential for airway obstruction and the need for ex utero intrapartum treatment (EXIT procedure) at delivery.
• CT scanning

  • CT scans are superior to MRIs in delineating bony deformation.
  • CT scans are superior to other modalities in detecting phleboliths, which were once considered pathognomonic of venous malformations. Phleboliths observed in lymphatic malformations are most likely caused by a previous intralesional hemorrhage.
  • Three-dimensional CT scans may be obtained to permit the fabrication of stereolithographic models with which to plan orthognathic surgical correction of the maxillofacial skeletal deformity at maturity.
• Plain radiography: Posteroanterior and lateral cephalometric radiographs are invaluable in diagnosing maxillofacial skeletal deformities secondary to lymphatic malformations.

Superficial lesions consist of dilated lymph vessels lined by flat endothelial cells in a discontinuous layer immediately subjacent to the oral epithelium. These lesions often replace the dermal papillae, but they can also extend into the deeper connective tissue.

Deeper lesions consist of irregular, dilated, and interconnected lymphatic vessels, some of which reveal macroscopic cyst formation (eg, cystic hygroma, cystic lymphangioma, lymphangioma cystoides). The walls of the vessels variably contain smooth muscle bundles. Lymphoid aggregates and germinal centers can be observed in both the surrounding tissues and the walls of the lesion. Cystic spaces generally contain a lightly eosinophilic, proteinaceous fluid with scant lymphocytes.

In contrast to vascular malformations, electron microscopy and immunohistochemical techniques demonstrate irregular and fragmented basal lamina in the lymphatic malformations.

• Lymphatic malformations in the oral cavity can be classified as superficial lesions and deep lesions on the basis of their histologic and clinical features.

  • Superficial lesions include lymphangioma simplex, lymphangioma circumscriptum, and capillary hemangioma.
  • Deep lesions are further divided into microcystic variants (eg, cavernous lymphangioma) and macrocystic variants (eg, lymphangioma cystoides, cystic lymphangioma, cystic hygroma).
• In the oral cavity, superficial and microcystic lesions are most common.
• Below the mandible and above the maxilla, macrocystic lesions predominate.
• Any lesion may comprise any or all of the histomorphologic variants.
• A staging system for cervical lymphatic malformations by de Serres is based on the extent of anatomical involvement. It has been validated in terms of its ability to predict the incidence of preoperative complications, postoperative complications, long-term morbidity, and risk of recurrence, which increase with the stage of the lesion. The system is perhaps better termed a classification because staging implies a progressive neoplastic behavior.

  • Stage/class I - Unilateral infrahyoid lesions
  • Stage/class II - Unilateral suprahyoid lesions
  • Stage/class III - Unilateral suprahyoid and infrahyoid lesions
  • Stage/class IV - Bilateral suprahyoid lesions
  • Stage/class V - Bilateral suprahyoid and infrahyoid lesions
  • Stage/class VI - Bilateral infrahyoid lesions