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 Table of Contents  
CASE REPORTS
Year : 2021  |  Volume : 4  |  Issue : 1  |  Page : 121-127

Melorheostosis of spine: A very rare clinical entity


Department of Orthopedics, Civil Hospital, Ahmedabad, Gujarat, India

Date of Submission07-Oct-2019
Date of Decision11-Dec-2019
Date of Acceptance21-Jan-2020
Date of Web Publication01-Oct-2020

Correspondence Address:
Harshil R Patel
5 Birva Row House, Near Bopal Gram Panchayat, Bopal, Ahmedabad-58, Gujarat.
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ISJ.ISJ_68_19

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  Abstract 

Melorheostosis is a medical developmental disorder and mesenchymal dysplasia in which bone cortex widens and becomes hyperdense in a sclerotomal distribution. Most of the cases reported till now are confined to appendicular skeleton, rarely affecting spine. It is well known by its characteristic appearance of “melting wax flowing down a candle” on radiographs. Here we report a rare case of melorheostosis of thoracic spine in a middle-aged male patient with features of myelopathy treated by early decompression surgery, leading to complete relief of symptoms postoperatively. Final follow-up was of 2 years. It is a very rare, benign and disabling entity, and the diagnosis is primarily a radiological one. Early diagnosis and decompression surgery leads to dramatic improvement in clinical outcome and prevents unwarranted biopsy.

Keywords: Laminectomy, melorheostosis, sclerotomal


How to cite this article:
Modi JV, Patel HR. Melorheostosis of spine: A very rare clinical entity. Indian Spine J 2021;4:121-7

How to cite this URL:
Modi JV, Patel HR. Melorheostosis of spine: A very rare clinical entity. Indian Spine J [serial online] 2021 [cited 2021 Apr 19];4:121-7. Available from: https://www.isjonline.com/text.asp?2021/4/1/121/308214




  Introduction Top


Melorheostosis is a medical developmental disorder and mesenchymal dysplasia in which bone cortex widens and becomes hyperdense in a sclerotomal distribution, proposed to be caused by a genetic mutation in LEMD3 gene. It was first described by Leri and Joanny in 1922,[1] hence also called Leri’s disease. Melorheostosis affects mainly the diaphysis of long bones, pelvis, and hand–feet. One bone (monostotic) or many bones (polystotic) may be affected, and either one side of body (hemimelic) or single limb (monomelic) may be affected. Most of the cases reported till now are confined to appendicular skeleton, rarely affecting axial skeleton. It is well known by its characteristic appearance of “melting wax flowing down a candle” on radiographs.

Involvement of spine is distinctly unusual,[2] and neurosurgical intervention is rarely necessary.[3] The purpose of this case report was to describe the typical presentation, course, and outcome of a patient diagnosed with spinal melorheostosis who underwent decompressive surgery followed by a comprehensive rehabilitation program and followed up to two years.


  Case History Top


A 40-year-old male, farmer by profession, presented with chief complaints of bilateral lower limb tingling, numbness, and difficulty in walking since last three months. He reported recurrent spasms, which caused his legs to go into rigid extension. His gait was unsteady, and he was not able to walk without support. It hampered his occupational abilities. Neurological examination revealed exaggerated lower limb reflexes with fair power and increased tone (grade 1) along with decreased sensation below D8 dermatome. He denied any problems with his bowel function but did report mild urinary urgency. Radiographs showed right-sided widening of sixth to eighth ribs with irregular borders and dense sclerosis along the ribs and anterolateral body of dorsal sixth to ninth vertebra. Computer tomography (CT) scans and magnetic resonance imaging (MRI) were performed, and both showed evidence of hyperostotic bone disease causing stenosis of 70%–80% of the spinal canal at multiple levels between D5 and D9. The patient underwent open biopsy procedure from right sixth rib at some cancer hospital before presenting to us, which revealed it to be ossified mass without any signs of malignancy. The patient underwent posterior dorsal laminectomy for decompression of the central canal as well as lateral recess using ultrasonic bone scalpel, from D5 to D9. Complete en masse lamina was removed in one piece from D5 to D9. Thorough decompression was performed without any fixation as the column was inherently stable. Neuromonitoring was not used. Postoperative neurology was same as before. He was put on vigilant gait training schedule from day one and stretching exercises to maximize the range of motion and mobility. On the third postoperative day, he had a steady bipedal unassisted gait and the lower limb tone was also normal. At the final follow-up of 2 years, he had no complaints, his bowel bladder functions were normal, and he was able to do his heavy chores regularly. Follow-up radiograph showed same sclerotomal pattern with postoperative laminectomy changes without instability.

The typical radiological features help in clear diagnosis of melorheostosis, avoiding unnecessary biopsy procedures. A very good clinical outcome was reported on prompt diagnosis and early intervention in such cases [Figure 1][Figure 2][Figure 3][Figure 4][Figure 5][Figure 6][Figure 7][Figure 8][Figure 9].
Figure 1: Radiographs showed right-sided widening of sixth to eighth ribs with irregular borders and dense sclerosis along the ribs and anterolateral body of dorsal sixth to ninth vertebra

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Figure 2: Three-dimensional computed tomography axial cut showing clearly dense sclerosis and hyperostosis along ribs and vertebra

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Figure 3: Three-dimensional computed tomography coronal cut showing clearly dense sclerosis and hyperostosis along ribs and vertebra

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Figure 4: Magnetic resonance imaging showing showed evidence of hyperostotic bone disease causing stenosis of 70%–80% of the spinal canal at multiple levels between D5 and D9

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Figure 5: Magnetic resonance imaging showed evidence of hyperostotic bone disease causing stenosis of 70%–80% of the spinal canal at multiple levels between D5 and D9

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Figure 6: Magnetic resonance imaging myelogram showed complete stenosis of spinal canal at multiple levels between D5 and D9

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Figure 7: Intraoperative image showing complete decompression of spinal cord after laminectomy

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Figure 8: En masse removed lamina showing cut edges using bone scalpel

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Figure 9: 2 year follow-up radiograph

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  Discussion Top


Since the original description of melorheostosis in 1922, more than 400 cases have been reported, of which most cases described lesion in appendicular skeleton. Literature reports regarding melorheostosis of spine are very scarce. We report a case of symptomatic middle-aged male patient having melorheostosis in dorsal spine, successfully treated with decompressive surgery. Its incidence is around 0.9 per million. This disease is nonhereditary and affects both sexes equally manifesting itself in early childhood and is evident by 20 years of age in approximately 40%–50% of cases.[4],[5] The consequences of sclerotic bone formation within the spinal canal can be precarious when considering the limited space available for spinal cord at dorsal level. Our patient had significant stenosis of the vertebral foramen due to hyperostosis, leading to compression of the cord with subsequent sensory, motor, and autonomic deficits.

Motimayaet al.[6] described the imaging findings of melorheostosis, involving the cervical and upper thoracic spine, but conservative management was elected because of lack of clinical and imaging changes for 8 years.

Robertson et al.[7] described a patient with a history of long-standing low-back discomfort associated with a diagnosis of melorheostosis with normal neurology. Radiologic testing revealed cortical sclerosis of the vertebral body wall, pedicle, and posterior elements of L2 and L3, as well as sclerosis of the left L5 inferior articular process, causing significant L5-S1 foraminal stenosis. Instrumented lumbosacral fusion with near-complete resolution of symptoms was reported 1 year after surgery.

Resnick[5] described similar myelopathy case due to melorheostosis from C5 to D4, having unbalanced gait and paraparesis, treated by decompressive surgery in the form of laminectomy. They reported immediate postoperative neurology worsening followed by striking improvement in outcome at 2-month follow-up, which was even better than the preoperative status.

Of the few cases reported in literature, we could infer that recovery of neurologic function seems to be favorable in patients with melorheostosis-associated myelopathy. However, due to severe paucity of documented cases of this rare condition, it is difficult to determine the prognosis with any certainty.

On imaging, differential diagnoses of melorheostosis include myositis ossificans, osteopetrosis, chronic osteomyelitis, parosteal and periosteal osteosarcoma, calcium pyrophosphate dihydrate (CPPD) deposition disease, osteoma, and Caffey disease.

Tumoral calcinosis of the spine, associated with systemic disorders of calcium metabolism or renal dialysis, is often not unilateral and appears primarily as extradural lesions with heterogeneous mixed signal intensity on both T1-weighted and T2-weighted images, which are often associated with the erosion of adjacent bone.

CPPD can occur as tumorlike lesions in the spine, typically located at the ligamentum flavum and synovial joints. The MRI findings of spinal CPPD are also similar to those for tumoral calcinosis, thus differing from melorheostosis.[8]

Although ivory osteomas can have histological features similar to melorheostosis, large osteomas of the spine are very rare and have been reported to involve only single vertebra. Heterotopic ossification, also referred to as myositis ossificans, typically occurs as lesions in soft tissue with predominant peripheral distribution of ossification and thus differs from the appearance of cortical-based hyperostosis seen with melorheostosis.

The imaging features of parosteal and periosteal osteosarcomas also differ markedly from melorheostosis because these tumors contain ossific mineralized matrix, often irregular and not uniformly attenuated on radiographs. Finally, the juxtacortical soft tissue masses of periosteal osteosarcomas typically cause extrinsic erosion of cortical bone, perpendicular periosteal reaction, with high signal intensity on T2-weighted images, which are findings not observed with melorheostosis.[9]

The diagnosis of melorheostosis was made on the basis of the characteristic distribution, location, and combined radiographic, CT, and MRI features of the abnormalities. The unilateral, sclerotomal, and multifocal cortical locations with a lack of interval change for the abnormalities in this report are characteristic for melorheostosis and are identical to prior reported imaging findings for biopsy-confirmed melorheostosis, involving lower thoracic and lumbar vertebrae.[10]


  Conclusion Top


Melorheostosis of spine is a very rare, benign, and disabling entity, and the diagnosis is primarily a radiological one. Thus, the knowledge of its classical findings and its pattern of involvement can prevent an unwarranted biopsy in patients. It may cause severe neuromuscular impairments due to spinal cord compression, but early decompression surgery leads to dramatic improvement in clinical outcome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Leri A, Joanny J Une affection non décrite des os hyperostose “en coulée” sur toute la longeur d’un member ou “melorhéostose.” Bull Mem Soc Med Hosp Paris 1922;46:1141-5.  Back to cited text no. 1
    
2.
Exergian FE, Soare NI, Duncan RW Vertebral melorheostosis. Case illustration. J Neurosurg 2001;95:278.  Back to cited text no. 2
    
3.
Lang G, Schroeder H, Warzok RW Melorheostosis—A very rare entity in neurosurgery. Neurosurg Rev 1993;16:229-32.  Back to cited text no. 3
    
4.
Rozencwaig R, Wilson MR, McFarland GB Jr. Melorheostosis. Am J Orthop (Belle Mead NJ) 1997;26:83-9.  Back to cited text no. 4
    
5.
Resnick D Diagnosis of Bone and Joint Disorders. 3rd ed. Philadelphia, PA: WB Saunders; 1995.  Back to cited text no. 5
    
6.
Motimaya AM, Meyers SP Melorheostosis involving the cervical and upper thoracic spine: Radiographic, CT, and MR imaging findings. AJNR Am J Neuroradiol 2006;27:1198-200.  Back to cited text no. 6
    
7.
Robertson PA, Don AS, Miller MV Painful lumbosacral melorheostosis treated by fusion. Spine (Phila Pa 1976) 2003;28:E234-8.  Back to cited text no. 7
    
8.
Shaffrey CI, Munoz EL, Sutton CL, Alston SR, Shaffrey ME, Laws ER Jr. Tumoral calcium pyrophosphate dihydrate deposition disease mimicking a cervical spine neoplasm: Case report. Neurosurgery 1995;37:335-9.  Back to cited text no. 8
    
9.
Jelinek JS, Murphey MD, Kransdorf MJ, Shmookler BM, Malawer MM, Hur RC Parosteal osteosarcoma: Value of MR imaging and CT in the prediction of histologic grade. Radiology 1996;201:837-42.  Back to cited text no. 9
    
10.
McCarthy M, Mehdian H, Fairbairn KJ, Stevens A Melorheostosis of the tenth and eleventh thoracic vertebrae crossing the facet joint: A rare cause of back pain. Skeletal Radiol 2004;33:283-6.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]



 

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