Osteoid osteoma mimicking monoarticular juvenile idiopathic arthritis in a girl.
Osteoid osteoma (OO) is a benign osteogenic neoplasm, usually affecting children and young adults, that is typically characterized by nocturnal pain and response to non-steroidal anti-inflammatory drugs. OO is frequently misdiagnosed because it mimics juvenile idiopathic arthritis (JIA), bone infection or malignancy. Herein we report the case of a girl who presented with chronic monoarthritis of the knee mimicking JIA. After 1 year, OO of the femoral distal metaphysis was diagnosed. OO was treated with computed tomography-guided radiofrequency ablation with disappearance of the symptoms and resolution of the neoplasm. No recurrences have been observed 3 years after the treatment. This case highlights that intra-articular or juxta-articular OO should be suspected in the case of misleading symptoms and signs, such as swelling, lack of typical pain and synovial thickening on ultrasound; needle biopsy of the lesion is necessary in the case of confusing imaging.
Department of Pediatrics, Immunology and Rheumatology Section, University of Pisa, Pisa, Italy.
Francesco
F
Massei
Department of Pediatrics, Immunology and Rheumatology Section, University of Pisa, Pisa, Italy.
Gianluigi
G
Laccetta
Department of Pediatrics, Immunology and Rheumatology Section, University of Pisa, Pisa, Italy.
Monica
M
Barrani
Orthopedic Division, University of Pisa, Pisa, Italy.
Luca
L
Fabbri
Department of Diagnostic Radiology, University of Pisa, Pisa, Italy.
Virna
V
Zampa
Department of Diagnostic Radiology, University of Pisa, Pisa, Italy.
Alessandro
A
Paolicchi
Division of Diagnostic and Interventional Radiology, University of Pisa, Pisa, Italy.
Roberto
R
Cioni
Department of Pathology, University of Pisa, Pisa, Italy.
Eugenio Mario
EM
Ciancia
Orthopedic Division, University of Pisa, Pisa, Italy.
Michelangelo
M
Scaglione
Department of Pediatrics, Immunology and Rheumatology Section, University of Pisa, Pisa, Italy.
Rita
R
Consolini
D001171:Arthritis, Juvenile / Q000175:diagnosis*; D001707:Biopsy, Needle; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000601:surgery; D017115:Catheter Ablation; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D005269:Femur; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D010017:Osteoma, Osteoid / Q000175:diagnosis* / Q000601:surgery; D014057:Tomography, X-Ray Computed
femur; juvenile idiopathic arthritis; needle biopsy; osteoid osteoma; radiofrequency ablation