Case report 81
Back pain in Duchenne muscular dystrophy: steroids are not always the culprit Lee S. Segala,b, Ryan Odgersb, David Carpentierib and M. Wade Shraderb We report on a child with Duchenne muscular dystrophy on prolonged corticosteroid treatment who presented with back pain and was subsequently found to have a monostotic fibrous dysplasia lesion of the spine. It is the intent of this case report to emphasize the need to maintain a high index of suspicion for other potential causes of back pain in Duchenne muscular dystrophy besides vertebral compression fractures. J Pediatr Orthop B 25:81–85 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Introduction
Journal of Pediatric Orthopaedics B 2016, 25:81–85 Keywords: Duchenne muscular dystrophy, fibrous dysplasia, spine a Department of Orthopaedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin and bPhoenix Children’s Hospital, Phoenix, Arizona, USA
Correspondence to Lee S. Segal, MD, Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, University of Wisconsin Medical Foundation Centennial Building, 1685 Highland Avenue, Madison, WI 53705-2281, USA Tel: + 1 608 263 3178; e-mail: [email protected]
Long-term use of corticosteroids in Duchenne muscular dystrophy (DMD) patients has been demonstrated to lessen the progressive decline in muscle strength and cardiopulmonary function, prolong ambulation, decrease the prevalence of scoliosis, and potentially increase life expectancy [1–6]. The long-term use of corticosteroids is not without potential side effects. These include weight gain, short stature, cataract formation, and osteopenia [7 –10]. Insufficiency fractures associated with the prolonged use of steroids secondary to osteopenia have been reported in DMD [4,11,12]. Back pain associated with vertebral compression fractures are common [11]. Thus, children with DMD on steroids are appropriately monitored for signs and symptoms of such compression fractures. We report a case of a child with DMD presenting with back pain, which upon further work-up was found to be due to monostotic fibrous dysplasia (MFD) of the spine. To the best of our knowledge, no previous association of DMD with MFD has been reported. It is the intent of this case report to emphasize the need to maintain a high index of suspicion for other potential causes of back pain in DMD, that other osseous and nonosseous lesions may be discovered with closer scrutiny of spinal radiographs.
level, despite the radiology report being interpreted as normal. A computed tomography scan was recommended for better delineation of the lesion at the L3 level, which showed a heterogenous expansile lesion within the right lamina of the L3 vertebra (Fig. 2). The differential diagnosis included osteoblastoma or an aneurysmal bone cyst involving the spine. An operative procedure was recommended to allow for complete excision of the lesion, posterior arthrodesis with spinal instrumentation, and rapid mobilization of the patient the following day, maintaining his ability to walk independently. The procedure involved complete excision of the expansile lesion (requiring removal of the L3 spinous process, the right L3 lamina, and the right L2–L3 and L3–L4 facet joints), with posterior spinal arthrodesis and instrumentation of L2–L4. Differing opinions were given for the histopathological diagnosis of the excised tissue (Fig. 3). The pathologists at our institution were steadfast in their diagnosis of fibrous dysplasia (FD) due to the relative lack of a prominent osteoblastic rimming about the osteoid bone. An external second opinion thought that the diagnosis was consistent with that of an osteoblastoma. Two years after surgery, the patient remained ambulatory and pain-free with regard to his back (Fig. 4).
Case report
Discussion
A 13-year-old boy with a history of DMD treated for 4 years with Deflazacort presented for routine follow-up with a new complaint of lower back pain. He remained ambulatory and only used a wheelchair for long distances. He had previously documented compression fractures of the lumbar spine and was being treated with Fosamax (a bisphosphonate medication). Radiographs obtained showed vertebral compression fractures, as well as a possible expansile lesion of the third lumbar (L3) vertebra (Fig. 1). A retrospective review of earlier radiographs revealed the expansile lesion to be present at the L3
DMD is an X-linked recessive disease characterized by progressive loss of functional muscle mass that starts at birth [13]. Untreated, DMD can progress to the loss of walking ability around the end of the first decade of life and death near the end of the second decade of life, typically due to cardiopulmonary compromise [1,14]. The introduction of corticosteroids in the management of DMD has been a significant advancement. Numerous studies have demonstrated the improvement in the natural history of the disease. Prolonged life span, prolonged ambulation, and a decreased need for spine surgery have
1060-152X Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
DOI: 10.1097/BPB.0000000000000158
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
82 Journal of Pediatric Orthopaedics B 2016, Vol 25 No 1
Fig. 1
Spinal radiographs showing an expansile lesion within the right lamina, part of the right pedicle and transverse process, and crossing the midline and involving the spinous process and a part of the left lamina of the L3 vertebrae.
Fig. 2
Computed tomography scan showing the heterogenous expansile lesion within the right lamina of the L3 vertebra.
been well documented in relation to the administration of corticosteroids [1,3,15]. Children with DMD, at baseline, have increased rates of low bone mineral density and subsequent fractures [12, 16,17]. Vestergaard et al. [12] reported on 139 patients with DMD or Becker muscular dystrophy and found significantly higher rates of upper extremity and lower
extremity fractures in these patients compared with normal controls. Unfortunately, the chronic use of glucocorticoid therapy potentially further compromises ‘bone health’, with increased risks for osteopenia, bone pain, and fragility or insufficiency fractures [12]. In an 8-year follow-up study of 79 patients with DMD, Houde and colleagues evaluated 37 DMD patients (47%)
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Back pain in DMD: a case report Segal et al. 83
nontreated group. In the same study, it was found that both treated and untreated patients suffered long-bone fractures at similar rates [3]. Biggar et al. [6] found similar results, with one in four DMD patients experiencing a long-bone fracture whether or not they were treated with steroids. They did not report on spinal fractures. King et al. [4] found significantly more spinal and long-bone fractures in treated versus nontreated patients in their review of 159 boys with DMD. No spinal fractures were observed in the nontreated patients. Compared with the other studies conducted at Canadian institutions, where Deflazacort was exclusively used, the patients in the report by King et al. were treated with either cortisone or Deflazacort [3,4,6].
Fig. 3
Histopathology of an L3 specimen, consistent with fibrous dysplasia with irregular-shaped spicules of woven bone surrounded by spindle cell stroma.
treated with Deflazacort for an average of 66 months. Seven patients in the treatment group had sustained vertebral fractures, whereas no fractures were observed in the
Regardless of the specific corticosteroid used, it has been consistently reported that DMD patients on prolonged treatment with steroids have significantly more fractures in the spine than those who are not treated. Bothwell and colleagues evaluated 33 boys retrospectively to determine the prevalence of vertebral fractures after starting corticosteroid treatment. The first fracture occurred after a latency of 40 months. Of the group, 75% had sustained a vertebral fracture by 100 months [11]. Of these fractures, 20–80% may be asymptomatic and only discovered on routine scoliosis-monitoring radiographs [3,6,11].
Fig. 4
Radiographs of the lumbar spine 2 years after arthrodesis and spinal instrumentation from L2 to L4.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
84 Journal of Pediatric Orthopaedics B 2016, Vol 25 No 1
In our patient presenting with new onset of back pain, vertebral compression fracture(s), for the reasons outlined above, should be the most likely etiology of his back pain. As reported, the patient had been receiving biphosphonate treatment for his previous vertebral compression fractures. Parenteral pamidronate has been reported to successfully control pain due to FD [18]. However, as this case report demonstrates, it is important to consider obtaining radiographs at a minimum to exclude less common causes of back pain. We cannot state with complete certainty that the patient’s back pain was directly related to the MFD spinal lesion, but rather, the MFD spinal lesion was suspected as the source of his back pain, as correlation does not imply causation. MFD of the spine, which was the cause of back pain in our patient, is a decidedly rare entity [19]. About 70–80% of cases of FD occur as a single lesion (monostotic) and tend to present as an incidental finding [20]. Symptomatic lesions may present with bone pain, visible deformity, or fracture [21]. In the series of Mancini et al. [22], the authors did not identify any patient with MFD and scoliosis, only observed in those with polyostotic FD or McCune–Albright syndrome. FD is a developmental abnormality of the bone in which failure of the remodeling process results in a lesion of immature bone and dysplastic fibrous tissue; it represents around 7% of benign bone tumors [23]. Common locations of MFD include the ribs, the craniofacial bones, and the long bones [24]. The association between MFD, DMD, and prolonged corticosteroid use is most likely a chance occurrence. FD is thought to be caused by a noninherited overexpression of the c-fos gene leading to increased adenylate cyclase activity, whereas DMD is caused by an X-linked mutation in the dystrophin gene that produces a dysfunctional protein [13,25]. There was a difference of opinion with regard to the diagnosis of the spinal lesion based on histopathologic examination. Other authors have also reported difficulties in the histopathologic diagnosis of painful spinal pathologies. Park et al. [26] reported that in cases of FD with blastic lesions, the differential diagnosis should include osteoblastoma. Kaur et al. [27] stated that FD of the bone may share many similarities with osteoblastoma. Reflecting these difficulties, an alternative histopathologic diagnosis of ‘benign fibro-osseous lesion with features of FD/osteoblastoma’ may be considered. Troop and Herring [28] presented a case report of a 12-year-old girl with monostotic FD of the L3 vertebra that was treated with curettage of the lesion and posterior arthrodesis from L2 to L3 without spinal instrumentation. Unlike this patient, our patient was treated with spinal instrumentation to allow for early mobilization, which must be adhered to in the postoperative period when caring for patients with DMD in order to maintain ambulation [29,30].
This case report highlights the need to consider less common causes of back pain in DMD and to carefully examine the spinal radiographs for other osseous and soft-tissue lesions. This is particularly important, owing to the increased use of corticosteroids and the risk for vertebral compression fractures in patients with DMD.
Acknowledgements Permission was received from the parents of the patient in this case report. Conflicts of interest
There are no conflicts of interest.
References 1
2
3
4
5
6
7
8
9
10
11
12
13 14
15
16 17
18
Lebel DE, Corston JA, McAdam LC, Biggar WD, Alman BA. Glucocorticoid treatment for the prevention of scoliosis in children with Duchenne muscular dystrophy: long-term follow-up. J Bone Joint Surg Am 2013; 95:1057–1061. Dooley JM, Gordon KE, MacSween JM. Impact of steroids on surgical experiences of patients with Duchenne muscular dystrophy. Pediatr Neurol 2010; 43:173–176. Houde S, Filiatrault M, Fournier A, Dubé J, D’Arcy S, Bérubé D, et al. Deflazacort use in Duchenne muscular dystrophy: an 8-year follow-up. Pediatr Neurol 2008; 38:200–206. King WM, Ruttencutter R, Nagaraja HN, Matkovic V, Landoll J, Hoyle C, et al. Orthopedic outcomes of long-term daily corticosteroid treatment in Duchenne muscular dystrophy. Neurology 2007; 68:1607–1613. Biggar WD, Politano L, Harris VA, Passamano L, Vajsar J, Alman B, et al. Deflazacort in Duchenne muscular dystrophy: a comparison of two different protocols. Neuromuscul Disord 2004; 14:476–482. Biggar WD, Harris VA, Eliasoph L, Alman B. Long-term benefits of deflazacort treatment for boys with Duchenne muscular dystrophy in their second decade. Neuromuscul Disord 2006; 16:249–255. Griggs RC, Moxley RT 3rd, Mendell JR, Fenichel GM, Brooke MH, Pestronk A, Miller JP. Clinical Investigation of Duchenne Dystrophy Group. Prednisone in Duchenne dystrophy. A randomized, controlled trial defining the time course and dose response. Arch Neurol 1991; 48:383–388. McAdam LC, Mayo AL, Alman BA, Biggar WD. The Canadian experience with long-term deflazacort treatment in Duchenne muscular dystrophy. Acta Myol 2012; 31:16–20. Bianchi ML, Mazzanti A, Galbiati E, Saraifoger S, Dubini A, Cornelio F, Morandi L. Bone mineral density and bone metabolism in Duchenne muscular dystrophy. Osteoporos Int 2003; 14:761–767. Mendell JR, Moxley RT, Griggs RC, Brooke MH, Fenichel GM, Miller JP, et al. Randomized, double-blind six-month trial of prednisone in Duchenne’s muscular dystrophy. N Engl J Med 1989; 320:1592–1597. Bothwell JE, Gordon KE, Dooley JM, MacSween J, Cummings EA, Salisbury S. Vertebral fractures in boys with Duchenne muscular dystrophy. Clin Pediatr (Phila) 2003; 42:353–356. Vestergaard P, Glerup H, Steffensen BF, Rejnmark L, Rahbek J, Moseklide L. Fracture risk in patients with muscular dystrophy and spinal muscular atrophy. J Rehabil Med 2001; 33:150–155. Sussman M. Duchenne muscular dystrophy. J Am Acad Orthop Surg 2002; 10:138–151. Manzur AY, Kuntzer T, Pike M, Swan A. Glucocorticoid corticosteroids for Duchenne muscular dystrophy. Cochrane Database Syst Rev 2008; 23: CD003725. Moxley RT 3rd, Pandya S, Ciafaloni E, Fox DJ, Campbell K. Change in natural history of Duchenne muscular dystrophy with long-term corticosteroid treatment: implications for management. J Child Neurol 2010; 25:1116–1129. Larson CM, Henderson RC. Bone mineral density and fractures in boys with Duchenne muscular dystrophy. J Pediatr Orthop 2000; 20:71–74. McDonald DG, Kinali M, Gallagher AC, Mercuri E, Muntoni F, Roper H, et al. Fracture prevalence in Duchenne muscular dystrophy. Dev Med Child Neurol 2002; 44:695–698. Chapurlat RD, Delmas PD, Liens D, Meunier PJ. Long-term effects of intravenous pamidronate in fibrous dysplasia of bone. J Bone Miner Res 1997; 12:1746–1752.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Back pain in DMD: a case report Segal et al. 85
19
20 21 22 23
24
Schoenfeld AJ, Koplin SA, Garcia R, Hornicek FJ, Mankin HJ, Raskin KA, et al. Monostotic fibrous dysplasia of the spine: a report of seven cases. J Bone Joint Surg Am 2010; 92:984–988. Park SK, Lee IS, Choi JY, Cho KH, Suh KJ, Lee JW, Song JW. CT and MRI of fibrous dysplasia of the spine. Br J Radiol 2012; 85:996–1001. DiCaprio MR, Enneking WF. Fibrous dysplasia. Pathophysiology, evaluation, and treatment. J Bone Joint Surg Am 2005; 87:1848–1864. Mancini F, Corsi A, De Maio F, Riminucci M, Ippolito E. Scoliosis and spine involvement in fibrous dysplasia of bone. Eur Spine J 2009; 18:196–202. Meredith DS, Healey JH. Twenty-year follow-up of monostotic fibrous dysplasia of the second cervical vertebra: a case report and review of the literature. J Bone Joint Surg Am 2011; 93:e74. Fitzpatrick KA, Taljanovic MS, Speer DP, Graham AR, Jacobson JA, Barnes GR, Hunter TB. Imaging findings of fibrous dysplasia with histopathologic and intraoperative correlation. Am J Roentgenol 2004; 182:1389–1398.
25
26 27 28
29 30
Candeliere GA, Glorieux FH, Prud’homme J, St-Arnaud R. Increased expression of the c-fos proto-oncogene in bone from patients with fibrous dysplasia. N Engl J Med 1995; 332:1546–1551. Park SK, Lee IS, Choi JY, Cho KH, Suh KJ, Lee JW, Song JW. CT and MRI of fibrous dysplasia of the spine. Br J Radiol 2012; 85:996–1001. Kaur H, Verma S, Jawanda MK, Sharma A. Aggressive osteoblastoma of the mandible. A diagnostic dilemma. Dent Res J 2012; 9:334–337. Troop JK, Herring JA. Monostotic fibrous dysplasia of the lumbar spine: case report and review of the literature. J Pediatr Orthop 1988; 8: 599–601. Siegel IM. Maintenance of ambulation in Duchenne muscular dystrophy. The role of the orthopedic surgeon. Clin Pediatr (Phila) 1980; 19:383–388. Smith SE, Green NE, Cole RJ, Robison JD, Fenichel GM. Prolongation of ambulation in children with Duchenne muscular dystrophy by subcutaneous lower limb tenotomy. J Pediatr Orthop 1993; 13:336–340.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Back pain in Duchenne muscular dystrophy: steroids are not always the culprit Lee S. Segala,b, Ryan Odgersb, David Carpentierib and M. Wade Shraderb We report on a child with Duchenne muscular dystrophy on prolonged corticosteroid treatment who presented with back pain and was subsequently found to have a monostotic fibrous dysplasia lesion of the spine. It is the intent of this case report to emphasize the need to maintain a high index of suspicion for other potential causes of back pain in Duchenne muscular dystrophy besides vertebral compression fractures. J Pediatr Orthop B 25:81–85 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Introduction
Journal of Pediatric Orthopaedics B 2016, 25:81–85 Keywords: Duchenne muscular dystrophy, fibrous dysplasia, spine a Department of Orthopaedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin and bPhoenix Children’s Hospital, Phoenix, Arizona, USA
Correspondence to Lee S. Segal, MD, Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health, University of Wisconsin Medical Foundation Centennial Building, 1685 Highland Avenue, Madison, WI 53705-2281, USA Tel: + 1 608 263 3178; e-mail: [email protected]
Long-term use of corticosteroids in Duchenne muscular dystrophy (DMD) patients has been demonstrated to lessen the progressive decline in muscle strength and cardiopulmonary function, prolong ambulation, decrease the prevalence of scoliosis, and potentially increase life expectancy [1–6]. The long-term use of corticosteroids is not without potential side effects. These include weight gain, short stature, cataract formation, and osteopenia [7 –10]. Insufficiency fractures associated with the prolonged use of steroids secondary to osteopenia have been reported in DMD [4,11,12]. Back pain associated with vertebral compression fractures are common [11]. Thus, children with DMD on steroids are appropriately monitored for signs and symptoms of such compression fractures. We report a case of a child with DMD presenting with back pain, which upon further work-up was found to be due to monostotic fibrous dysplasia (MFD) of the spine. To the best of our knowledge, no previous association of DMD with MFD has been reported. It is the intent of this case report to emphasize the need to maintain a high index of suspicion for other potential causes of back pain in DMD, that other osseous and nonosseous lesions may be discovered with closer scrutiny of spinal radiographs.
level, despite the radiology report being interpreted as normal. A computed tomography scan was recommended for better delineation of the lesion at the L3 level, which showed a heterogenous expansile lesion within the right lamina of the L3 vertebra (Fig. 2). The differential diagnosis included osteoblastoma or an aneurysmal bone cyst involving the spine. An operative procedure was recommended to allow for complete excision of the lesion, posterior arthrodesis with spinal instrumentation, and rapid mobilization of the patient the following day, maintaining his ability to walk independently. The procedure involved complete excision of the expansile lesion (requiring removal of the L3 spinous process, the right L3 lamina, and the right L2–L3 and L3–L4 facet joints), with posterior spinal arthrodesis and instrumentation of L2–L4. Differing opinions were given for the histopathological diagnosis of the excised tissue (Fig. 3). The pathologists at our institution were steadfast in their diagnosis of fibrous dysplasia (FD) due to the relative lack of a prominent osteoblastic rimming about the osteoid bone. An external second opinion thought that the diagnosis was consistent with that of an osteoblastoma. Two years after surgery, the patient remained ambulatory and pain-free with regard to his back (Fig. 4).
Case report
Discussion
A 13-year-old boy with a history of DMD treated for 4 years with Deflazacort presented for routine follow-up with a new complaint of lower back pain. He remained ambulatory and only used a wheelchair for long distances. He had previously documented compression fractures of the lumbar spine and was being treated with Fosamax (a bisphosphonate medication). Radiographs obtained showed vertebral compression fractures, as well as a possible expansile lesion of the third lumbar (L3) vertebra (Fig. 1). A retrospective review of earlier radiographs revealed the expansile lesion to be present at the L3
DMD is an X-linked recessive disease characterized by progressive loss of functional muscle mass that starts at birth [13]. Untreated, DMD can progress to the loss of walking ability around the end of the first decade of life and death near the end of the second decade of life, typically due to cardiopulmonary compromise [1,14]. The introduction of corticosteroids in the management of DMD has been a significant advancement. Numerous studies have demonstrated the improvement in the natural history of the disease. Prolonged life span, prolonged ambulation, and a decreased need for spine surgery have
1060-152X Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
DOI: 10.1097/BPB.0000000000000158
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
82 Journal of Pediatric Orthopaedics B 2016, Vol 25 No 1
Fig. 1
Spinal radiographs showing an expansile lesion within the right lamina, part of the right pedicle and transverse process, and crossing the midline and involving the spinous process and a part of the left lamina of the L3 vertebrae.
Fig. 2
Computed tomography scan showing the heterogenous expansile lesion within the right lamina of the L3 vertebra.
been well documented in relation to the administration of corticosteroids [1,3,15]. Children with DMD, at baseline, have increased rates of low bone mineral density and subsequent fractures [12, 16,17]. Vestergaard et al. [12] reported on 139 patients with DMD or Becker muscular dystrophy and found significantly higher rates of upper extremity and lower
extremity fractures in these patients compared with normal controls. Unfortunately, the chronic use of glucocorticoid therapy potentially further compromises ‘bone health’, with increased risks for osteopenia, bone pain, and fragility or insufficiency fractures [12]. In an 8-year follow-up study of 79 patients with DMD, Houde and colleagues evaluated 37 DMD patients (47%)
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Back pain in DMD: a case report Segal et al. 83
nontreated group. In the same study, it was found that both treated and untreated patients suffered long-bone fractures at similar rates [3]. Biggar et al. [6] found similar results, with one in four DMD patients experiencing a long-bone fracture whether or not they were treated with steroids. They did not report on spinal fractures. King et al. [4] found significantly more spinal and long-bone fractures in treated versus nontreated patients in their review of 159 boys with DMD. No spinal fractures were observed in the nontreated patients. Compared with the other studies conducted at Canadian institutions, where Deflazacort was exclusively used, the patients in the report by King et al. were treated with either cortisone or Deflazacort [3,4,6].
Fig. 3
Histopathology of an L3 specimen, consistent with fibrous dysplasia with irregular-shaped spicules of woven bone surrounded by spindle cell stroma.
treated with Deflazacort for an average of 66 months. Seven patients in the treatment group had sustained vertebral fractures, whereas no fractures were observed in the
Regardless of the specific corticosteroid used, it has been consistently reported that DMD patients on prolonged treatment with steroids have significantly more fractures in the spine than those who are not treated. Bothwell and colleagues evaluated 33 boys retrospectively to determine the prevalence of vertebral fractures after starting corticosteroid treatment. The first fracture occurred after a latency of 40 months. Of the group, 75% had sustained a vertebral fracture by 100 months [11]. Of these fractures, 20–80% may be asymptomatic and only discovered on routine scoliosis-monitoring radiographs [3,6,11].
Fig. 4
Radiographs of the lumbar spine 2 years after arthrodesis and spinal instrumentation from L2 to L4.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
84 Journal of Pediatric Orthopaedics B 2016, Vol 25 No 1
In our patient presenting with new onset of back pain, vertebral compression fracture(s), for the reasons outlined above, should be the most likely etiology of his back pain. As reported, the patient had been receiving biphosphonate treatment for his previous vertebral compression fractures. Parenteral pamidronate has been reported to successfully control pain due to FD [18]. However, as this case report demonstrates, it is important to consider obtaining radiographs at a minimum to exclude less common causes of back pain. We cannot state with complete certainty that the patient’s back pain was directly related to the MFD spinal lesion, but rather, the MFD spinal lesion was suspected as the source of his back pain, as correlation does not imply causation. MFD of the spine, which was the cause of back pain in our patient, is a decidedly rare entity [19]. About 70–80% of cases of FD occur as a single lesion (monostotic) and tend to present as an incidental finding [20]. Symptomatic lesions may present with bone pain, visible deformity, or fracture [21]. In the series of Mancini et al. [22], the authors did not identify any patient with MFD and scoliosis, only observed in those with polyostotic FD or McCune–Albright syndrome. FD is a developmental abnormality of the bone in which failure of the remodeling process results in a lesion of immature bone and dysplastic fibrous tissue; it represents around 7% of benign bone tumors [23]. Common locations of MFD include the ribs, the craniofacial bones, and the long bones [24]. The association between MFD, DMD, and prolonged corticosteroid use is most likely a chance occurrence. FD is thought to be caused by a noninherited overexpression of the c-fos gene leading to increased adenylate cyclase activity, whereas DMD is caused by an X-linked mutation in the dystrophin gene that produces a dysfunctional protein [13,25]. There was a difference of opinion with regard to the diagnosis of the spinal lesion based on histopathologic examination. Other authors have also reported difficulties in the histopathologic diagnosis of painful spinal pathologies. Park et al. [26] reported that in cases of FD with blastic lesions, the differential diagnosis should include osteoblastoma. Kaur et al. [27] stated that FD of the bone may share many similarities with osteoblastoma. Reflecting these difficulties, an alternative histopathologic diagnosis of ‘benign fibro-osseous lesion with features of FD/osteoblastoma’ may be considered. Troop and Herring [28] presented a case report of a 12-year-old girl with monostotic FD of the L3 vertebra that was treated with curettage of the lesion and posterior arthrodesis from L2 to L3 without spinal instrumentation. Unlike this patient, our patient was treated with spinal instrumentation to allow for early mobilization, which must be adhered to in the postoperative period when caring for patients with DMD in order to maintain ambulation [29,30].
This case report highlights the need to consider less common causes of back pain in DMD and to carefully examine the spinal radiographs for other osseous and soft-tissue lesions. This is particularly important, owing to the increased use of corticosteroids and the risk for vertebral compression fractures in patients with DMD.
Acknowledgements Permission was received from the parents of the patient in this case report. Conflicts of interest
There are no conflicts of interest.
References 1
2
3
4
5
6
7
8
9
10
11
12
13 14
15
16 17
18
Lebel DE, Corston JA, McAdam LC, Biggar WD, Alman BA. Glucocorticoid treatment for the prevention of scoliosis in children with Duchenne muscular dystrophy: long-term follow-up. J Bone Joint Surg Am 2013; 95:1057–1061. Dooley JM, Gordon KE, MacSween JM. Impact of steroids on surgical experiences of patients with Duchenne muscular dystrophy. Pediatr Neurol 2010; 43:173–176. Houde S, Filiatrault M, Fournier A, Dubé J, D’Arcy S, Bérubé D, et al. Deflazacort use in Duchenne muscular dystrophy: an 8-year follow-up. Pediatr Neurol 2008; 38:200–206. King WM, Ruttencutter R, Nagaraja HN, Matkovic V, Landoll J, Hoyle C, et al. Orthopedic outcomes of long-term daily corticosteroid treatment in Duchenne muscular dystrophy. Neurology 2007; 68:1607–1613. Biggar WD, Politano L, Harris VA, Passamano L, Vajsar J, Alman B, et al. Deflazacort in Duchenne muscular dystrophy: a comparison of two different protocols. Neuromuscul Disord 2004; 14:476–482. Biggar WD, Harris VA, Eliasoph L, Alman B. Long-term benefits of deflazacort treatment for boys with Duchenne muscular dystrophy in their second decade. Neuromuscul Disord 2006; 16:249–255. Griggs RC, Moxley RT 3rd, Mendell JR, Fenichel GM, Brooke MH, Pestronk A, Miller JP. Clinical Investigation of Duchenne Dystrophy Group. Prednisone in Duchenne dystrophy. A randomized, controlled trial defining the time course and dose response. Arch Neurol 1991; 48:383–388. McAdam LC, Mayo AL, Alman BA, Biggar WD. The Canadian experience with long-term deflazacort treatment in Duchenne muscular dystrophy. Acta Myol 2012; 31:16–20. Bianchi ML, Mazzanti A, Galbiati E, Saraifoger S, Dubini A, Cornelio F, Morandi L. Bone mineral density and bone metabolism in Duchenne muscular dystrophy. Osteoporos Int 2003; 14:761–767. Mendell JR, Moxley RT, Griggs RC, Brooke MH, Fenichel GM, Miller JP, et al. Randomized, double-blind six-month trial of prednisone in Duchenne’s muscular dystrophy. N Engl J Med 1989; 320:1592–1597. Bothwell JE, Gordon KE, Dooley JM, MacSween J, Cummings EA, Salisbury S. Vertebral fractures in boys with Duchenne muscular dystrophy. Clin Pediatr (Phila) 2003; 42:353–356. Vestergaard P, Glerup H, Steffensen BF, Rejnmark L, Rahbek J, Moseklide L. Fracture risk in patients with muscular dystrophy and spinal muscular atrophy. J Rehabil Med 2001; 33:150–155. Sussman M. Duchenne muscular dystrophy. J Am Acad Orthop Surg 2002; 10:138–151. Manzur AY, Kuntzer T, Pike M, Swan A. Glucocorticoid corticosteroids for Duchenne muscular dystrophy. Cochrane Database Syst Rev 2008; 23: CD003725. Moxley RT 3rd, Pandya S, Ciafaloni E, Fox DJ, Campbell K. Change in natural history of Duchenne muscular dystrophy with long-term corticosteroid treatment: implications for management. J Child Neurol 2010; 25:1116–1129. Larson CM, Henderson RC. Bone mineral density and fractures in boys with Duchenne muscular dystrophy. J Pediatr Orthop 2000; 20:71–74. McDonald DG, Kinali M, Gallagher AC, Mercuri E, Muntoni F, Roper H, et al. Fracture prevalence in Duchenne muscular dystrophy. Dev Med Child Neurol 2002; 44:695–698. Chapurlat RD, Delmas PD, Liens D, Meunier PJ. Long-term effects of intravenous pamidronate in fibrous dysplasia of bone. J Bone Miner Res 1997; 12:1746–1752.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
Back pain in DMD: a case report Segal et al. 85
19
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