I Overview
Odontogenic keratotic cysts are benign cystic tumors that originate from the primitive tooth germ or plate. Formerly known as odontogenic keratocyst, it was renamed as odontogenic keratocystic cystic tumor by the WHO in 2005. It mostly occurs in young adults. Shan Xiaofeng, Department of Maxillofacial Surgery, Peking University Oral Hospital
Clinical manifestations
1. It can occur in any part of the jaw bone, most commonly in the mandibular third molar area and mandibular ascending branch.
2. The tumor grows slowly and there is no conscious symptom at the beginning. If the tumor continues to grow, the bone will gradually expand to the surrounding area, then facial deformity will be formed. If the tumor develops further, the surface bone will become very thin and have a ping-pong-like sensation when palpated, and can make a parchment-like cracking sound. When the tumor absorbs all the bone on the surface, there will be fluctuating sensation on palpation. When the bone around the tumor is destroyed to a certain extent, pathological fracture may occur.
3.Most of them swell to the buccal side, and some of them swell to the lingual side and penetrate the lingual bone wall.
4.Keratinized cystic tumor of maxilla may enter maxillary sinus and nasal cavity, leading to compression and displacement of adjacent organs and corresponding symptoms, such as compression of the upper wall of maxillary sinus may displace the eyeball, produce diplopia and affect vision.
5.The tumor area and adjacent teeth can be compressed, and the periapical bone can be resorbed to loosen and displace the teeth.
6.Keratocystic tumor can be accompanied by missing teeth or multiple teeth. If the tooth in the tumor area is loosened and lost or extracted, sebum-like material can be seen in the extraction wound.
7.It can be single or multiple, but single is more common.
8.Nevus-like basal cell carcinoma syndrome, also known as “multiple basal cell nevus syndrome”: multiple keratocystic tumors are accompanied by skin basal cell nevus or basal cell carcinoma, bifurcation ribs, orbital distance widening, cranial abnormalities, cerebellar sickle calcification and other symptoms. If there are only multiple keratocystic tumors without basal cell nevi (carcinoma) and other symptoms, it can also be called “keratocystic tumor syndrome”.
III Biological behavior
Keratocystic tumor can be transformed into or accompanied by enamel cell tumor, and it has the ability to recur and become cancerous. The domestic reported carcinoma rate is 2.65%. Carcinoma cases are characterized by age above 40 years, history of recurrent infections, multicystic nature, pathology typical of squamous carcinoma, and significantly enhanced expression of proliferating cell nuclear antigen (PCNA).
IV Diagnosis
1.Preliminary diagnosis can be made based on medical history and clinical manifestations.
2.Puncture: yellowish-white keratin-like (sebum-like) material can be seen in the puncture fluid. Further clarification can be made by keratin staining of the aspirate
3.X-ray: clear round or oval transparent shadow with neat edges, often surrounded by a clear white bony reaction line, sometimes the edges may not be neat.
4.Pathological examination to confirm the diagnosis.
V Treatment
Treatment of odontogenic keratocystic tumor is similar to that of odontogenic cyst, but because it is more likely to recur (its recurrence rate is 3%-60%) and may become malignant, the treatment has its own characteristics and requires more thorough surgical scraping. After scraping the cyst wall, the bone wound is coated with an etching agent such as phenol or silver nitrate, or cryotherapy is added to destroy the subcapsules and reduce recurrence. Partial removal of bone at the periphery of the cyst may also be considered if necessary. If the lesion is too extensive or repeatedly recurring keratocystic tumor, removal of the jawbone together with the soft tissue of the lesion should be considered, and in principle, bone grafting should be done at the same time.