Extrinsic odontogenic cysts .

  • Cysts are common antral lesions, and can be either intrinsic or extrinsic.
  • Odontogenic cysts located in the posterior area of the maxilla, such as: radicular, residual, dentigerous and odontogenic keratocysts  are the most common odontogenic extrinsic cystic lesions.
  • Radiographic findings: Round, dome-shaped opacity in the floor of the maxillary sinus with a well-defined radio-opaque rim. Large cysts may cause total antrum occlusion with displacement of the adjacent teeth.

Case 1

Radicular cyst of the left maxillary 1st molar, causing elevation of  the sinus floor and mucosal thickening.

Case 2

Large odontogenic cyst causing a total opacification of the right maxillary sinus, right nasal cavity end right ethmoid cells.