The Bulky Dermoid Cyst of the Floor of the Mouth

Bulky dermoid cysts of the floor of the mouth are very rare and may induce functional disorder. We present a 68-year-old Chinese woman who presented a painless swelling in right mandibular. Physical examination revealed a painless, soft, poor mobility, doughlike mass swelling which was reached to the floor of the mouth, and MRI showed a circumscribed mass of about 20.0×10.0×12.0 cm size. After complete excision of the cyst through an extraoral approach, histology diagnosed dermoid cyst. Dermoid cyst is uncommon found in the floor of the mouth, where there is a soft, painless, associated dyspnea, dysphagia and dysarthria. Imaging may assist diagnosis. Definitive diagnosis is founded on the histology specimen. According to the location and size of the cyst on each occasion, enucleation via intraoral or extraoral approach will be chosen treatment for cyst in the floor of the mouth. Although malignant degeneration of dermoid cyst of the floor of mouth is extremely rare, there are also such a situation reports. Thus, it is important to remove a cyst before the opportunity for malignancy.