Differentiation of jaw cyst and enamel-forming cell tumor

Based on the incidence and surgical approach, enameloblastoma needs to be differentiated mainly from odontogenic keratocysts and other non-keratocysts. Non-keratinizing cysts such as tooth-containing cysts, apical cysts, residual cysts and facial cleft cysts have certain characteristics in terms of site of origin, internal structure and clinical manifestations, which are not difficult to distinguish from enameloblastoma. Since enameloblastoma and odontogenic keratotic cysts are similar to some extent in terms of onset site, lesion morphology and biological behavior, and the treatment method is different from other non-keratotic cysts, the differentiation of the two is the focus and difficulty of differential diagnosis of cystic lesions in jaws. The aggressiveness of enameloblastoma is higher than that of keratinized cysts, causing more destruction of the surrounding bone than keratinized cysts and easily invading the surrounding soft tissues. Root resorption caused by enameloblastoma is more often serrated or truncated, causing loss of adjacent teeth, whereas root resorption caused by keratocyst is more often oblique and less often causes loss of adjacent teeth. Enamel cell tumors are mostly mixed cystic and solid with irregular thick walls and papillary protrusions or wall nodules; keratocysts are purely cystic with uniform thin walls. The septum is often composed of soft tissue and a small amount of bony components and is thicker; the septum of keratocysts is slender, intact, and thin. The MR signal of the cystic part of enameloblastoma is mostly long T1 and long T2 signal, and sometimes short T1 signal is seen in intracapsular hemorrhage; the T2 signal of the cystic contents of keratinized cyst is significantly lower than that of enameloblastoma because it is rich in keratinized protein and solid cholesterol crystals, and this sign is considered to be an important feature to distinguish the nature of the cystic fluid between the two. On CT or MR enhancement, the cyst wall, partitions, papillae and wall nodules of enameloblastoma are significantly enhanced; the cyst wall and partitions of keratotic cysts are not enhanced.