Vancamp, E

Vanderschueren, G

Vanhoenacker, Filip

Abstract: Osteoid osteoma (OO) is a painful, benign bone-forming lesion, which often poses a diagnostic challenge. The aetiology of OO is still poorly understood. Although not generally accepted, an association with previous trauma or infection has occasionally been suggested. We present a case of an OO 12 years following an ulnar fracture. Radiologists should consider OO as a potential delayed complication of a previous fracture. Persistent pain at a previous fracture site should alert the clinician to request cross-sectional imaging. CT scanning plays a pivotal role in the correct diagnosis of OO

Vancamp, E.

Vanderschueren, G.

Institutional Repository Universiteit Antwerpen

Post-traumatic osteoid osteoma in an 18-year-old adolescent

Osteoid osteoma (OO) is a painful, benign bone-forming lesion, which often poses a diagnostic challenge. The aetiology of OO is still poorly understood. Although not generally accepted, an association with previous trauma or infection has occasionally been suggested. We present a case of an OO 12 years following an ulnar fracture. Radiologists should consider OO as a potential delayed complication of a previous fracture. Persistent pain at a previous fracture site should alert the clinician to request cross-sectional imaging. CT scanning plays a pivotal role in the correct diagnosis of OO

Ghent University Academic Bibliography

Received:30 March 2015Revised:12 May 2015Accepted:19 May 2015Cite this article as:Vancamp E, Vanhoenacker FM, Vanderschueren G. Post-traumatic osteoid osteoma in an 18-year-old adolescent. BJR Case Rep2015; 1: 20150141.CASE REPORTPost-traumatic osteoid osteoma in an 18-year-oldadolescent1E VANCAMP, MD,1,2,3F M VANHOENACKER, MD, PhD and4G VANDERSCHUEREN, MD, PhD1Department of Radiology, Antwerp University Hospital, Edegem, Belgium2Department of Radiology, Sint-Maarten General Hospital, Duffel-Mechelen, Belgium3Department of Radiology, Ghent University Hospital, Ghent, Belgium4Department of Radiology, University Hospital Gasthuisberg, Leuven, BelgiumAddress correspondence to: Dr E VancampE-mail: ellen_vc@hotmail.comABSTRACTOsteoid osteoma (OO) is a painful, benign bone-forming lesion, which often poses a diagnostic challenge. The aetiologyof OO is still poorly understood. Although not generally accepted, an association with previous trauma or infection hasoccasionally been suggested. We present a case of an OO 12 years following an ulnar fracture. Radiologists shouldconsider OO as a potential delayed “complication” of a previous fracture. Persistent pain at a previous fracture site shouldalert the clinician to request cross-sectional imaging. CT scanning plays a pivotal role in the correct diagnosis of OO.SUMMARYDiagnosing osteoid osteoma (OO) can be a significantchallenge owing to its ambiguous presentation and unclearaetiology. This article describes a case of OO at the site of aprevious ulnar fracture, sustained 12 years previously. Thepatient experienced nocturnal pain at the fracture site,which was relieved by salicylates. The final diagnosis wasprimarily based on imaging findings. Performing a CTscan is mandatory when OO is suspected. Although theassociation between OO and previous trauma remains con-troversial, persistent pain at a previous fracture site shouldraise the index of clinical suspicion of OO as a post-trau-matic “complication”. Internal fixation may be the mostimportant predisposing factor in this process.CASE PRESENTATIONAn 18-year-old female was referred to our institution com-plaining of pain in the left mid-forearm. Previous medicalhistory included a fracture of both radius and ulna 12 yearspreviously, which had been successfully treated with reduc-tion and by intramedullary pinning (Figure 1). Severalmonths before the current referral, there was an insidiousonset of pain, which was gradually increasing, more intenseat night and relieved by salicylates. On physical examina-tion, there was moderate swelling at the old fracture site.There were no signs of local or systemic inflammation.Conventional radiographs of the left forearm revealed alucent area adjacent to the previous fracture site with sur-rounding sclerosis and cortical thickening (Figure 2).Subsequent MRI showed an oval intracortical lesion in theulna, with central hypointensity to skeletal muscle on bothT1 and T2 weighted images. After administration of gado-linium contrast, there was marked peripheral enhancementof the lesion with perilesional bone marrow and soft-tissueoedema (Figure 3). Because imaging characteristics werehighly suggestive of an OO, an additional CT scan was per-formed (Figure 4). This examination showed pathogno-monic features of an OO with a central calcified nidus atthe site of the previous fracture.CLINICAL PRESENTATIONOO is a benign osteoblastic lesion characterized by a coreor nidus of osteoid tissue that is surrounded by a zone ofreactive bone formation. OOs comprise around 11% of allbenign primary bone tumours. They are more prevalent inmales and usually occur during the second or third decadeof life. Since the lesion is richly innervated by nerve fibres,pain is the most common symptom. The pain is graduallyprogressive, often more intense at night and typicallyrelieved by the administration of salicylates. Sometimes thepain is referred to adjacent joints or is poorly localized,contributing to the difficulty in diagnosing the tumour.Superficial lesions may present with swelling, tendernessand redness, and therefore may mimic the clinical pictureof osteomyelitis. Depending on its location within thebone, the lesion is classified as cortical, medullary (cancel-lous) or subperiosteal. OO usually occurs in the shaft ofthe long bones, especially the femur and the tibia.1BJR|case reports doi: 10.1259/bjrcr.20150141© 2015 The Authors. Published by the British Institute of Radiology. This is an open access article under the terms of the Creative Commons Attribution4.0 International License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source arecredited.AETIOLOGYThe pathogenesis of OO has not yet been fully understood.Whether it represents a true neoplasm, a reactive lesion inresponse to trauma, inflammation or infection, or an unusualhealing or vascularization process is still a matter of debate.Most reports do not mention any aetiological relationshipbetween trauma and formation of OO. More recently, however,some authors have documented OO occurring after traumaticevents or fractures. Our review of the literature has identifiedseven cases of OO as a delayed sequelae of a sustained fracturein adolescents. The predominantly affected bone was the tibia,followed by the femur and the radius, with pain presentingbetween 2 and 8 years after trauma.2–8 In five cases, the fracturewas reduced and treated by internal fixation. It has beensuggested that invagination of the periosteum during fracture,reduction or pinning may act as a predisposing factor for thedevelopment of OO,3 which is also in line with the observationsin our case. However, since no scientific study has proven thishypothesis so far, the association between traumatic events andOO remains doubtful.IMAGING FINDINGSOn plain radiographs, an OO typically presents as a round oroval intracortical radiolucent focus representing the nidus thatcontains a variable amount of central mineralization, accompa-nied by reactive sclerosis and cortical thickening. Extensivesclerosis may obscure nidus visualization on plain radiographs.CT scanning is much more accurate in detecting the nidus inFigure 1. (a) Initial radiograph (posteroanterior film) 12 yearspreviously shows an oblique fracture at the mid-diaphysis ofboth radius and ulna. (b) Postoperative anteroposterior filmdepicting intramedullary pinning and beginning signs of callusformation. The radius demonstrates nearly complete bonybridging. The ulna shows partial but incomplete bony bridging.a bFigure 2. Anteroposterior (a) and lateral (b) plain radiographsat current admission reveal a focal intracortical lucency (whitearrow) adjacent to the previous fracture site with surroundingsclerosis and cortical thickening (white arrowheads).a bFigure 3. (a) Coronal T1 weighted image. (b) Coronal T2 weighted image. (c) Axial T2 weighted image. (d) Axial fat-suppressedT1 weighted image after administration of gadolinium contrast. (e) Axial subtraction of the images before and after gadolinium con-trast administration. MRI shows a focal intracortical lesion in the ulna with low central signal intensity and mineralization on both T1and T2weighted images (white arrows). After administration of gadolinium contrast, there is marked peripheral enhancement of thelesion with perilesional bonemarrow and soft-tissue oedema (white arrowheads).d ea b cBJR|case reports E Vancamp et al2 of 3 birpublications.org/bjrcr BJR Case Rep;1:20150141the sclerotic area. The nidus has a low attenuation, although acentral area of high attenuation, representing mineralized oste-oid, is often seen. Surrounding reactive sclerosis ranges frommild sclerosis of the cortex to extensive periosteal reaction andnew bone formation. On MRI, the nidus is of low-to-interme-diate signal intensity on both T1 and T2 weighted images,depending on the amount of cortical mineralization. Adminis-tration of gadolinium-based contrast material may demonstratestrong enhancement of the nidus. Oedema in the adjacentbone marrow and soft tissue may also be seen on T2 weightedimages and on contrast-enhanced images. MRI may be non-specific and may mimic other diseases (e.g. stress fracture orosteomyelitis) if extensive surrounding bone marrow oedemaobscures the nidus.1DIFFERENTIAL DIAGNOSISThe main differential diagnosis includes cortical osteitis and lon-gitudinal stress fracture. Septic cortical osteitis is a rare subgroupof bone infection caused by haematogenous spread that is pre-dominantly or exclusively located in the cortex of long tubularbones. It usually affects adolescents and young adults. Plainradiographs may reveal focal cortical osteolysis along with thelong axis of the bone with a central linear density and limitedperiosteal reaction. CT scanning is the preferred technique todetect an intracortical sequestrum of dead bone resulting in the“cortical split sign”. Unlike the osteolysis in cortical osteitis, thelucent area in OO is smaller and has more smooth, round mar-gins. A longitudinal stress fracture can also cause an intracorticallucency, which has a more linear shape compared with an ovalor rounded shape in OO.1,9TREATMENTOOs are known to be self-limiting tumours that can be treatedconservatively with salicylates. However, the response to salicy-lates is variable and most patients are unable to continue thetreatment regimen because of persistent pain. Surgical excisionis not always straightforward because of the inherent inability tolocate the nidus during surgery. Furthermore, removal of largeramounts of bone is associated with a risk of fracture. Therefore,most OOs are currently treated by CT-guided thermocoagula-tion or radiofrequency ablation (RFA).10 In our case, CT-guidedpercutaneous curettage was performed, followed by RFA proce-dure. The patient recovered soon and at the 6-month follow-up,she was completely pain free.LEARNING POINTS1. Unexplained post-traumatic pain at a fracture sitewarrants further investigation by imaging.2. CT scan is the preferred technique for detection andcharacterization of OO.3. The exact pathogenesis of OO remains a matter ofdebate.4. Although a post-traumatic aetiology has been suggestedin the literature, this is not generally accepted as themain pathogenic mechanism.5. Based on the existing literature, internal fixation of thefracture may be a predisposing factor for development ofan OO several years following trauma.REFERENCES1. Chai JW, Hong SH, Choi JY, Koh YH,Lee JW, Choi JA, et al. Radiologicdiagnosis of osteoid osteoma: fromsimple to challenging findings.Radiographics 2010; 30: 737–49. doi: 10.1148/rg.3030951202. Baron D, Soulier C, Kermabon C, Leroy JP,Le Goff P. [Post-traumatic osteoid osteoma.apropos of 2 cases and review of theliterature]. Rev RhumMal Osteoartic 1992;59: 271–5.3. Adil A, Hoeffel C, Fikry T. Osteoid osteomaafter a fracture of the distal radius. Am JRoentgenol 1996; 167: 145–6. doi: 10.2214/ajr.167.1.86593594. Soon M, Low CK, Chew J. Osteoid osteomaafter a stress fracture of the tibia: a casereport. Ann Acad Med Singapore 1999; 28:877–8.5. Grenard N, Duparc F, Roussignol X,Chomant J, Muller JM, Dujardin F, et al.Osteoid osteoma after an old femoral shaftfracture. Rev Chir Orthop Reparatrice ApparMot 2001; 87: 503–5.6. Schulze W, Richter J, Kuhnen C,Henschel MG, Muhr G. Osteoid osteomathat occurred in a former fracturesite. Clin Orthop Relat Res 2001;387: 200–6. doi: 10.1097/00003086-200106000-000277. Espandar R, Radmehr A, Mohammadi MA,Saberi S, Haghpanah B. Fracture-site osteoidosteoma in a 26-year-old man. Am J Orthop(Belle Mead NJ) 2012; 41: E57–60.8. Riley ND, Camilleri D, McNally MA.Osteoid osteoma following fractureof the distal tibia: a case report andliterature review. Injury Extra2014; 45: 69–72. doi: 10.1016/j.injury.2014.06.0119. Goosens V, Vanhoenacker FM, Samson I,Brys P. Longitudinal cortical split signas a potential diagnostic feature forcortical osteitis. JBR-BTR 2010;93: 77–80.10. Motamedi D, Learch TJ, Ishimitsu DN,Motamedi K, Katz MD, Brien EW.Thermal ablation of osteoid osteoma:overview and step-by-step guide.Radiographics 2009; 29: 2127–41. doi: 10.1148/rg.297095081Figure 4. (a) Axial CT image. (b) Coronal reformatted CTimage. CT visualization of a cortical nidus in the ulna, sugges-tive of an osteoid osteoma.a bCase report: Post-traumatic osteoid osteoma in an 18-year-old adolescent BJR|case reports3 of 3 birpublications.org/bjrcr BJR Case Rep;1:20150141

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Post-traumatic osteoid osteoma in an 18-year-old adolescent

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