Epidermoid cyst of the floor of the mouth: two case reports

INTRODUCTION: Epidermoid cysts that appear in the midline floor of the mouth are, usually, a result of entrapped ectodermal tissue of the first and second branchial arches, which fuse during the third and fourth weeks in utero. The incidence in the floor of the mouth of the oral cavity is rare and development sites are the sublingual, submaxillary and submandibular spaces. It was present two cases of epidermoid cyst of the floor of the mouth and discussed the different surgical approaches for this lesion. CASES PRESENTATION: Two cases of midline epidermoid cysts of the floor of the mouth are presented, evaluating the different surgical approaches. The preoperative assessment was made using ultrasonography and computed tomography in both cases. Regarding surgical techniques used, a transcutaneous approach was adopted when the cysts were under the geniohyoid muscle and a midline incision of the oral mucosa along the lingual frenulum was used for sublingual cysts. During the postoperative course, there were no complications, except for mild edema in one case. Follow-up ranged between 5 months and 4 years; no recurrence or malignant changes were observed. CONCLUSIONS: Surgery of epidermoid cyst of the floor of the mouth is the treatment of choice. Access depends on the lesion's location in relation to the mylohyoid or geniohyoid muscles. If the cyst is located over the mylohyoid, surgery is carried out only through the oral cavity, whereas the extraoral incision was necessary only when the cysts were under the geniohyoid muscle.