[Management of lymphatic malformations in oral and maxillofacial regions: the rationale according to the new classification]

Abstract

According to the classification of ISSVA, Waner and Suen, the traditionally called lymphangiomas are now referred to as lymphatic malformations, including both macrocystic and microcystic lesions. They are commonly seen vascular anomalies, and most frequently diagnosed at birth and most often occur in the head and neck area. The etiology of lymphatic malformations is still unknown, resulting in a variety of treatment modalities. This paper reviewed the recent literatures with respect to the indications, contraindications, advantages and disadvantages of surgical excision, sclerotherapy and laser ablation of lymphatic malformations of the head and neck, with detailed discussion of the advances in molecular biology and clinical treatment prospects. It is concluded that although lymphatic malformations are benign lesions, they seldom involute spontaneously. Of all vascular malformations, lymphatic malformations are the most difficult to be eradicated. Their infiltrating nature coupled with the difficulty in distinguishing involved important structures of the head and neck from adjacent normal tissues makes complete surgical extirpation even more difficult. The likelihood of postsurgical recurrence and complications is thus higher than other vascular lesions. Although many treatment protocols are available in clinic, indications, contraindications, advantages and disadvantages exist in each modality. The selection of treatment modalities should depend on the patients' status and techniques available. The treatment protocol should be individualized and comprehensive as well as sequential, in order to obtain the best treatment outcomes. In general, treatment will vary according to the depth and the extent of the lesions. Superficial mucosal microcystic lesions and cervicofacial macrocystic lesions are amenable to ablation with sclerotherapy using Bleomycin and OK-432 with the advantages of the absence of a surgical scar. The sclerosing agent OK-432 is effective for macrocystic lymphatic malformations but showed less promise for microcystic lesions, mixed lesions, and lesions outside the head and neck region. In addition, superficial mucosal microcystic lesions are also amenable to CO2 laser therapy. Deeper microcystic lesions are still challenging head and neck surgeons, which are usually extensive and sometimes need to be resected in stages, and even may be impossible to be completely removed. Somnoplasty shows promise for reduction of tongue lymphatic malformations. Surgical excision, staged when necessary, continues to be integral to management in many cases, but should not be overused without consideration of the histologic types and extent. Localized mucosal microcystic lesions and major cervicofacial macrocystic lesions are amenable to primary excision. Care should be exercised in identifying and preserving important cervical and facial structures because anatomical planes are often distorted. Combined sequential approach is recommended for mixed lesions as well as extensive lesions involving both the mucosa and soft tissues.