Introduction: Dermoid cyst (DC) is a slow-growing benign developmental cysts that arises from ectodermal tissue and can occur anywhere in the body, with only 34% occurring in the head and neck region, of which 6.5% are located in the mouth floor and rarely in the upper lip. It usually presents as painless, slow-growing lesion with doughy consistency and is often soft and well encapsulated - generally observed on the second to third decade of life. Objective: The objective of this article is to report a case of DC, focusing on its clinical and histopathological characteristics, and to discuss possible clinical presentations to assist in the diagnosis of this rare lesion in the oral cavity. Case Report: A 4-year-old female was referred for evaluation of an asymptomatic swelling in the left upper lip mucosa region lasting 1 year. Extraoral clinical examination showed no alterations. Intraoral clinical examination revealed the presence of a single painless well-defined nodular, sessile, non-tender swelling covered by normal oral mucosa, and located in the upper labial mucosa. An excisional biopsy was performed, and microscopic examination revealed a cystic cavity covered by orthokeratinized stratified squamous epithelium with hair follicles and sebaceous glands found within the fibrous wall. Patient recovery was uneventful and there are no signs of local recurrence in a two-year clinical follow-up. Conclusion: DC can occur anywhere in the body, but once in the oral cavity, it is rarely observed in the upper lip.

Introduction:The evolution of chemo and radiotherapy, added to the increased frequency in its use, have led to an increase in the survival rate of pediatric patients with head and neck cancer. Thus, the effects of this therapy are increasingly common, and may affect even the teeth in formation. Objective: Conduct a literature review on the main dental anomalies of development in patients undergoing chemo and radiotherapy. Material and methods: The databases "Pubmed", "Google Scholar" and "Science Direct" were consulted using the keywords "dental alterations", "children", "dentistry", "cancer", "chemotherapy" and " radiotherapy". Twenty-seven articles published in English were selected. Results:Based on the articles included in the study, the effects of chemoradiotherapy on developing teeth can be both quantitative and qualitative. Those patients who underwent treatment during childhood, in this literature review, were between 0.8 and 15 years old. The main dental anomalies found include microdontia, hypodontia and root anomalies. In addition, it was also observed that the late effects of the therapy vary according to the radiation dose and the chemotherapy dose. Conclusions: Although there are few studies on dental alterations caused by chemotherapy and radiotherapy, it is necessary to implement protocols aimed at oral care during and after treatment to reduce the incidence and severity of such complications.