Figure 1
Computed Tomography (CT)
Uncommon cause of lower back pain during childhood.
SectionMusculoskeletal system
Case TypeClinical Cases
AuthorsDaniel Eiroa, Luisa Nieto Morales, Adán Bello Báez, Víctor Vázquez Sánchez, Arsenio Cavada Laza.
Connected authors
13 years, female
Clinical History
A 13 year-old female patient with no history of previous trauma, referred with lower back pain that has been present for two years. The orthopaedic surgeon requested an X-ray.
Imaging Findings
Our patient underwent conventional X-ray, computed tomography (CT) and magnetic resonance imaging (MRI).
Imaging revealed a radiolucent oval image (nidus) in the posterior aspect of the right iliac bone, with a sclerotic dot inside. Also, a thick solid regular sclerotic cortical thickening surrounding the nidus is seen. This is the typical presentation of an osteoid osteoma.
Imaging revealed a radiolucent oval image (nidus) in the posterior aspect of the right iliac bone, with a sclerotic dot inside. Also, a thick solid regular sclerotic cortical thickening surrounding the nidus is seen. This is the typical presentation of an osteoid osteoma.
Discussion
Osteoid osteomas (OO) are benign bone tumors composed of osteoblasts which tend to be small (less than 2 cm in diameter) and surrounded by a solid periosteal reaction. The histological appearance is that of a fibrovascular stroma with numerous osteoblasts, osteoid tissue, well-formed woven bone, and giant cells [1, 3].
It is a benign skeletal neoplasm of unknown aetiology which typically presents in children (particularly adolescents), although the age range of presentation is between the ages of 10 and 35 years. Males are affected more commonly than females. The classic presentation is that of progresive focal bone pain at the site of the tumour. The pain worsens at night and increases with activity; it is dramatically relieved with small doses of Nonsteroidal Anti-inflammatory Drugs. Soft tissue swelling may occur and if close to a growth plate, accelerated growth may be evident, presumably related to hyperaemia. When the lesion is intra-capsular, presentation is more atypical, and more likely mimics and inflammatory arthropathy or synovitis. Joint effusion is often present [2].
Radiography is the initial examination and may be the only examination required [1]. Although it can be normal, the typical features of osteoid osteomas in plain films are those of a solid periosteal reaction with cortical thickening and a well circumscribed lucent central region (nidus) [3]. CT is the technique of choice for the characterization of the lesion and is also useful for precise localization of the nidus. It may also be used for guiding percutaneous ablation and it typically shows a focally lucent nidus within surrounding sclerotic reactive bone and with or without a central sclerotic dot. The specificity of the MRI is lower compared to CT because the nidus is not as well depicted as in CT. Also, the hyperaemia and the bone marrow oedema secondary to it may lead to misinterpretation of the lesion as it being aggressive [1, 3].
The differential diagnosis that should be made when the aforementioned imaging features are found comprise eosinophilic granuloma (EG), stress fractures and septic cortical osteitis (SCO). SCO shows more irregular margins and the cortical is interrupted at some point. Stress fractures also show an interruption of the cortex. EG is more frequent in long bones and may show a soft-tissue mass and features of aggresivity [4, 5].
The treatment of OO may be conservative (NSAIDs for 3-6 months), surgical (curettage of the lesion) or minimally invasive (CT-guided radiofrequency ablation) [2, 6].
Our patient underwent open surgery and the OO was histologically confirmed.
It is a benign skeletal neoplasm of unknown aetiology which typically presents in children (particularly adolescents), although the age range of presentation is between the ages of 10 and 35 years. Males are affected more commonly than females. The classic presentation is that of progresive focal bone pain at the site of the tumour. The pain worsens at night and increases with activity; it is dramatically relieved with small doses of Nonsteroidal Anti-inflammatory Drugs. Soft tissue swelling may occur and if close to a growth plate, accelerated growth may be evident, presumably related to hyperaemia. When the lesion is intra-capsular, presentation is more atypical, and more likely mimics and inflammatory arthropathy or synovitis. Joint effusion is often present [2].
Radiography is the initial examination and may be the only examination required [1]. Although it can be normal, the typical features of osteoid osteomas in plain films are those of a solid periosteal reaction with cortical thickening and a well circumscribed lucent central region (nidus) [3]. CT is the technique of choice for the characterization of the lesion and is also useful for precise localization of the nidus. It may also be used for guiding percutaneous ablation and it typically shows a focally lucent nidus within surrounding sclerotic reactive bone and with or without a central sclerotic dot. The specificity of the MRI is lower compared to CT because the nidus is not as well depicted as in CT. Also, the hyperaemia and the bone marrow oedema secondary to it may lead to misinterpretation of the lesion as it being aggressive [1, 3].
The differential diagnosis that should be made when the aforementioned imaging features are found comprise eosinophilic granuloma (EG), stress fractures and septic cortical osteitis (SCO). SCO shows more irregular margins and the cortical is interrupted at some point. Stress fractures also show an interruption of the cortex. EG is more frequent in long bones and may show a soft-tissue mass and features of aggresivity [4, 5].
The treatment of OO may be conservative (NSAIDs for 3-6 months), surgical (curettage of the lesion) or minimally invasive (CT-guided radiofrequency ablation) [2, 6].
Our patient underwent open surgery and the OO was histologically confirmed.
Differential Diagnosis List
Osteoid Osteoma
Eosinophilic granuloma
Osteoid osteoma
Intracortical abscess
Stress fracture
Septic Cortical Osteitis
Final Diagnosis
Osteoid Osteoma
References
[1] Jee Won Chai, Sung Hwan Hong, Ja-Young Choi, Young Hwan Koh, Joon Woo Lee, Jung-Ah Choi, Heung Sik Kang (2010) Radiologic Diagnosis of Osteoid Osteoma: From simple to challenging findings. Radiographics 30:737-749 (PMID: 20462991)
[2] Lee EH, Shafi M, Hui JH (2006) Osteoid Osteoma: a current review. Journal of Pediatric Orthopedics 26(5):695-700 (PMID: 16932114)
[3] Kransdorf MJ, Stull MA, Gilkey FW, Moser RP (1991) Osteoid Osteoma. Radiographics 11(4):671-696 (PMID: 1887121)
[4] Goosens V, Vanhoenacker FM, Samson I, Brys P (2010) Longitudinal cortical split sign as a potential diagnostic feature for cortical osteitis. JBR-BTR 93(2):77-80 (PMID: 20524515)
[5] David R, Oria RA, Kumar R, Singleton EB, Lindell MM, Shirkoda A, Madewell JE (1989) Radiologic features of eosinophilic granuloma of bone. American Journal of Roentgenology 153(5): 1021-1026 (PMID: 2801420)
[6] Barei DP, Moreau G, Scarborough MT, Neel MD (2000) Percutaneous radiofrequency ablation of osteoid osteoma. Clin Orthop Relat Res 373: 115-124 (PMID: 10810468)
Case information
| URL: | https://www.eurorad.org/case/13046 |
| DOI: | 10.1594/EURORAD/CASE.13046 |
| ISSN: | 1563-4086 |
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Figure 2
Conventional X-Ray
Area of increased density due to sclerosis in the iliac bone adjacent to the right sacroiliac joint (arrows). Normal dimensions of the right sacroiliac joint space .
Figure 3
Magnetic Resonance Imaging (MRI)
MRI. T1-weighted oblique coronal image showing an excentrically located cortical defect associated to sclerosis of the adjacent bone marrow (arrowheads).
MRI. STIR oblique coronal.
Right iliac bone oval lesion with a thick hypointense rim in keeping with sclerosis (arrowheads) of the bone marrow. Slight ill-defined hyperintensity of the adjacent gluteus maximus, consistent with oedema (circled).
Computed Tomography (CT)
CT scan showing a regular cortical thickening with a central lucency, which is the nidus (arrowhead).
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Note the central sclerotic dot inside the oval lucency.
Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Canary Islands, Spain.
Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Canary Islands, Spain.
Conventional X-Ray
Area of increased density due to sclerosis in the iliac bone adjacent to the right sacroiliac joint (arrows). Normal dimensions of the right sacroiliac joint space .
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Magnetic Resonance Imaging (MRI)
MRI. T1-weighted oblique coronal image showing an excentrically located cortical defect associated to sclerosis of the adjacent bone marrow (arrowheads).
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
MRI. STIR oblique coronal.
Right iliac bone oval lesion with a thick hypointense rim in keeping with sclerosis (arrowheads) of the bone marrow. Slight ill-defined hyperintensity of the adjacent gluteus maximus, consistent with oedema (circled).
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.
Department of Radiology, Hospital Universitario Nuestra Señora de Candelaria, Tenerife, Spain.