title: Osteoid osteomas: a pain in the night diagnosis.
abstract: Osteoid osteoma is a common benign bone-forming lesion that is composed of a nidus of vascular osteoid tissue and woven bone lined by osteoblasts. It is frequently associated with considerable surrounding inflammation. The diagnosis is usually straightforward when imaging reveals a radiolucent nidus surrounded by variable degrees of reactive sclerosis. However, the diagnosis can be elusive when osteoid osteomas occur in atypical locations, as they may have a nonspecific and misleading appearance on different imaging modalities, particularly on MRI. The purpose of this pictorial essay is to review the typical and atypical features of osteoid osteomas on different imaging modalities, and the appearance of osteoid osteomas in different locations. We also review growth disturbances caused by osteoid osteomas and potential mimickers, with imaging characteristics that can aid in diagnosis.
authors.affiliation: Department of Radiology, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, 34th St. and Civic Center Blvd., Philadelphia, PA 19104, USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Laurence
authors.forename: Monica
authors.initials: M
authors.lastname: Epelman
authors.forename: Richard I
authors.initials: RI
authors.lastname: Markowitz
authors.forename: Camilo
authors.initials: C
authors.lastname: Jaimes
authors.forename: Diego
authors.initials: D
authors.lastname: Jaramillo
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Chauvin
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000150:complications / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010017:Osteoma, Osteoid / Q000150:complications / Q000175:diagnosis*; D010146:Pain / Q000175:diagnosis* / Q000209:etiology; D014057:Tomography, X-Ray Computed / Q000379:methods*