Static bone cavities were first reported by Stafne in 1942 and are considered localized bone recesses in the lingual cortical bone of the mandible. This diseased tissue has been reported as salivary gland (mainly submandibular gland) tissue, but its etiology remains unclear; several mechanisms have been proposed, but a consensus has yet to be reached.

　In addition, since it is rare to show enlargement in size, and this disease remains clinically asymptomatic, long-term follow-up observations are often made while evaluating images such as panoramic radiographs and CT without aggressive surgical invasion.

　We studied a static bone cavity that increased in size from a red bean to the tip of the thumb at 4 years 3 months. We performed minimally invasive surgical removal by an endoscopic intraoral approach for definite diagnosis and early recovery after surgery. The pathological diagnosis was adipose tissue, and the patient has no symptoms as of 1 year 7 months after the operation.