Background : Malar bone cysts are very rare. Literature suggests three patterns of development: (a) Residual cyst of retained deciduous roots with metaplasia of the odontogenic epithelium into respiratory epithelium. (b) Fissural cyst of the zygomatico-maxillary suture. (c) Connection to the maxillary sinus with subsequent epithelial proliferation.

Case : 34 years old man, consulting by swelling of two years of development in right malar area, painless, hard and bony consistency, net limits and covered by normal-appearing skin without signs of inflammation or infectious. The last two months show sporadic pain. His complaint is primarily aesthetic given the degree of growth causing facial asymmetry. TAC reveals homogeneous bone cavity with net limits on the zygoma body and immediately adjacent to the superior-external prolongation of ipsilateral maxillary sinus. Excisional biopsy was performed with malar bone plasty and immediate placement of a titanium mesh. Histopathology showed ciliated columnar cells like those in the upper respiratory tract, acute and chronic inflammatory cells and hemorrhagic areas.

Conclusions : Surgical bone remodeling returns the symmetric projection of zygomatic area. The use of titanium mesh contributes to soft tissue support avoiding collapse. Histopathological study is essential to clarify the cause and establish an accurate prognostic.

Key words : Zygoma; bone cyst