The incidence of LCH is about 4–5 cases per million per year for children under 15 years old [1]. The clinical symptoms of LCH vary a lot since the affected organs differ in patients. The lesions often occur in the bone and the skin in pediatric patients. Skull is the most often involved bone lesion. Only 7–10% of cases exhibit oral abnormality [4]. The oral manifestations of LCH include palatal mucosa with reddish or strawberry appearance, irregular ulcerated lesions on oral mucosa with periodontal involvement, and floating teeth observed by panoramic radiograph [2, 5, 6]. The rarity of LCH and the nonspecific oral lesions make the diagnosis of LCH patients only with oral involvement difficulty. The CBCT results of this patient elucidated that the bone damage progresses rapidly after 6-month interval, implying the great significance of early diagnosis and timely treatment.
The diagnosis of LCH depends on the clinical presentations, radiographic evaluation and histopathological features. The finding of Birbeck granules in LCH cells by electron microscopy was required to get the definitive diagnosis [7]. However, the detection of Birbeck granules by electron microscopy needs special instruments. The positive rate is low and the cost is high. Its diagnostic value has been replaced by a cell-surface receptor–langerin, which induces the formation of Birbeck granule [1].
The etiology and pathogenesis of LCH remain controversial, with two main arguments, one being the reactive disorders caused by the aberrant immune system and the other being the neoplastic dysfunction [8]. An overall BRAF mutation frequency of 48.5% indicated that LCH is a neoplasm in nature [9]. Patients with BRAF V600E mutation may have a higher recurrence rate.
Currently, LCH is classified into two categories according to the organs and systems affected, namely single-system LCH and multisystem LCH. Single-system LCH is further divided into unifocal lesion and multifocal lesions. Multisystem LCH is defined as risk organ positive multisystem LCH when the liver, lung, spleen or bone marrow is involved. Otherwise, it is diagnosed as risk organ negative multisystem LCH [10].
Appropriate treatment for LCH patients depends on the site and the dispersion status of affected organs, the phase of lesions and the healing procedure. Surgical procedures can be used for biopsy and curettage for the accessible maxillofacial LCH lesions. It is not suggested to remove all the lesions and the involved teeth with enough bone support may be maintained without influencing the prognosis of LCH [11]. Low-dose radiation therapy can be adopted in maxillofacial LCH cases in the management of unavailable, multifocal or recurrent lesions [12, 13]. The side effects of radiation on the growth of teeth and bone should be concerned in the following oral health management. For maxillofacial LCH patients, chemotherapy is also recommended protocol [8]. A combination of prednisone and vinblastine, employed in this case, is considered as the standard initial therapy for patients requiring systemic treatment. Treatment duration of 12 months is better than 6 months in decreasing the reactivation of the disease [14]. LCH patients with BRAF mutation may showed resistance and poor short-term response to chemotherapy [15]. Targeted therapy of BRAF inhibitor, such as Vemurafenib, is considered as an additional tool [10].
Oral health management for children during the entire growth and development is advocated [16]. Oral hygiene instructions, prevention and treatment of dental caries, regular fluoride application and follow-up should be commonly implemented for LCH children in pediatric clinic. The promotion of soft tissue health, such as topical application of chlorhexidine, should also be taken into consideration in the case of mucosal ulcer, gingival necrosis and periodontal inflammation. Space management and occlusal recovery is necessary for LCH patients with tooth loss. Monitoring the growth of teeth and bone should be highlighted during the follow-up sessions for children with LCH.
In summary, the case report presents the case of a 2-year, 4-month-old LCH patient with progressive destruction of jaws caused by the delayed treatment due to the global outbreak of COVID-19. The CBCT analysis after an interval of 6 months reminded us the great significance of early diagnosis and treatment of LCH. The diagnosis of LCH requires histological and immunophenotypic examination of lesional tissue. Bridges should be built with pediatric specialists to provide an appropriate and sufficient treatment. Comprehensive oral health management will facilitate the growth and development of the teeth, as well as the occlusion and the jaws for children with LCH.
