Learning Radiology xray montage

Osteoma of the Paranasal Sinus


General Considerations

  • Most common tumor of the paranasal sinuses
  • Most frequently seen in the frontal and ethmoid sinuses
  • Benign tumor of membranous bone consisting of dense, compact bone
  • Majority of paranasal osteomas are discovered serendipitously
  • In the skull, they usually arise from the outer table

Clinical Findings

  • Most are asymptomatic
  • Rarely, large osteoma in the frontal or ethmoid region may displace globe forward and cause proptosis
  • Obstruction of a sinus ostium may lead to infection or formation of a mucocele
  • Very rarely, an osteoma may erode through the dura leading to cerebrospinal fluid rhinorrhea or intracranial infection

Imaging Findings

  • Well-circumscribed, sharply-marginated round and very dense lesions usually less than 2 cm in size
  • Usually grow into the sinus
  • Multiple paranasal osteomas are found in Gardner’s syndrome
    • Multiple osteoma of the mandible and maxilla, along with the frontal, sphenoid and ethmoid sinuses, rarely the long bones or phalanges
    • Cutaneous and soft tissue tumors
    • Association between colonic polyps with a predilection to malignant degeneration


Osteoma of the Frontal Sinus. Two frontal views of the skull demonstrate an incidental rounded, sclerotic lesion growing into the right frontal sinus (white arrows).