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| CASE REPORT |
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| Year : 2022 | Volume
: 19
| Issue : 2 | Page : 88-91 |
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Osteochondroma of the dorsal spine presenting as thoracic myelopathy: A rare case report
HD Bharath1, R Krishnakumar1, Suranjana Ravi2
1 Department of Spine Surgery, Medical Trust Hospital, Kochi, Kerala, India
2 Department of Orthopaedic Surgery, Soundarapandian Bone and Joint Hospital and Research Institute Private Limited, Chennai, Tamil Nadu, India
| Date of Submission | 19-Nov-2022 |
| Date of Decision | 07-Dec-2022 |
| Date of Acceptance | 13-Dec-2022 |
| Date of Web Publication | 09-Feb-2023 |
Correspondence Address:
R Krishnakumar
Department of Spine Surgery, Medical Trust Hospital, Kochi, Kerala
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/joasis.joasis_37_22
Osteochondroma is commonly found in the appendicular skeleton, though, relatively rarely, they occur in the spine, especially in the thoracic pedicle. A thorough radiographic workup is mandatory for a diagnosis. This is a case of a 13-year-old boy who developed gradual weakness over the lower limbs for the past 6 months, which worsened rapidly to 2/5 motor power over the last 3 weeks. A multidetector computed tomography suggested the diagnosis of a solitary osteochondroma of the D6 pedicle. Laminectomy and costotransversectomy with partial facetectomy and complete excision of the tumor with posterior instrumentation were done. Histopathological biopsy confirmed the tumor to be an osteochondroma. The power of the lower limbs improved postoperatively with physiotherapy to 3/5 at 6 weeks, 4/5 at 3-month follow-up, and 5/5 at 6-month follow-up. At 6-year follow-up, the patient is doing absolutely fine without any residual weakness or neurological deficit. Osteochondroma of the spine is rare. However, if they do occur, they usually need to be thoroughly investigated for accurate diagnosis and precise surgical treatment. These tumors could be presented with just a back pain or with progressing neurological deficits. A high index of suspicion and wide options of evaluation and management could change the course of the disease and the functional outcome of the patient.
Keywords: Myelopathy, osteochondroma, spine, thoracic
How to cite this article:
Bharath H D, Krishnakumar R, Ravi S. Osteochondroma of the dorsal spine presenting as thoracic myelopathy: A rare case report. J Orthop Assoc South Indian States 2022;19:88-91 |
How to cite this URL:
Bharath H D, Krishnakumar R, Ravi S. Osteochondroma of the dorsal spine presenting as thoracic myelopathy: A rare case report. J Orthop Assoc South Indian States [serial online] 2022 [cited 2023 Mar 27];19:88-91. Available from: https://www.joasis.org/text.asp?2022/19/2/88/369411 |
| Introduction | |  |
Osteochondromas are more of a developmental anomaly than a true neoplasm, originating as small cartilaginous nodules within the periosteum. It is produced by a progressive endochondral ossification of a growing cartilaginous cap. It usually presents during the period of rapid growth and is usually found in the metaphysis of a long bone. Although it is rare to find these tumors in the spine, it is not an uncommon site. The clinical presentation varies from chronic dull aching pain to complete or incomplete neurological deficits depending on the severity and vicinity of the tumor to the spinal cord or neural structures.
| Case Report | | |
A 13-year-old boy developed weakness of the lower limbs for the past 6 months, worsened rapidly over the past 3 weeks. The weakness was progressive and was more on the left side. The power of the hip flexors was 3/5. With the knee extensors, ankle flexors and extensors was 2/5 on both sides. The deep tendon reflexes were exaggerated, with a well-sustained clonus and a positive Babinski sign. There were decreased sensations over all the dermatomes of the lower limbs. The bowel and bladder habits were unaffected. He was able to stand and walk a few steps with the help of support. Using a standard classification for grading of thoracic myelopathy, the Aminoff and Logue's score of disability [Figure 1], the clinical grade was determined to be Grade 4. A multidetector computed tomography (MDCT) of the spine showed an osteochondroma of the D6 vertebra, arising from the pedicle [Figure 2]a, [Figure 2]b, [Figure 2]c. The tumor was significantly compressing the cord, which was almost completely compressed at the D6 level with myelomalacic changes on magnetic resonance imaging (MRI) [Figure 3]. A laminectomy with costotransversectomy with a partial facetectomy with complete excision biopsy of the tumor with posterior instrumentation one level above and below was planned under neuromonitoring. However, during the laminectomy phase, there was a sudden loss of motor evoked potential [Figure 4]a and [Figure 4]b. Therefore, the surgery was stopped, and a wake-up test was done. The patient did not move the legs during the wake-up test. The laminectomy was completed, and the patient was shifted for emergency MRI scanning. The MRI showed cord edema [Figure 5], and the patient was started on intravenous methyl prednisolone. The patient started regaining the leg movements after 4 h. The patient continued to improve during the postoperative phase. After 2 weeks, the patient underwent the second stage of the procedure, wherein complete facetectomy followed by costotransversectomy and resection of the pedicle from the base with removal of the osteochondroma [Figure 6]a and [Figure 6]b and posterior instrumentation were done as planned. The patient was followed up with MDCT spine [Figure 7]a and [Figure 7]b at 6 weeks and 3 months, and the power of the hip, knee, and ankle flexors and extensors was found to be 3/5 which improved to 4/5 at 3 months. He is walking normally at 6 months with a 5/5 power. At 6-year follow-up, the patient is absolutely doing fine with no residual weakness or neurological deficit. | Figure 2: (a-c) Preoperative CT scan coronal, sagittal, and axial view showing an osteochondroma of the D6 pedicle. CT: Computed tomography
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 | Figure 3: Preoperative MRI scan sagittal view showing an osteochondroma D6 pedicle causing compression on the spinal cord. MRI: Magnetic resonance imaging
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 | Figure 4: (a) Baseline motor evoked potential, (b) Sudden drop in baseline motor evoked potential
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 | Figure 6: (a) Intraoperative picture showing the left side costotransversectomy at D6, (b) Excised osteochondroma in toto
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 | Figure 7: Postoperative CT scan showing decompression and tumor excision at D6 level, (a) axial view, (b) sagittal view. CT: Computed tomography
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| Discussion | | |
Osteochondroma is seen with an equal frequency in both sexes, and their incidence reduces after the first three decades of life. Representing 35%–50% of all benign tumors and 8%–15% of all primary bone tumors, they are the most common benign tumors.[1] Usually, they are found located in flat or long bones. The pathogenesis remains unclear, though it is established that the origin is not from a previous injury to the bone. Recent studies have pointed toward a genetic cause, suggesting that the disease is an autosomal-dominant hereditary disease, with the EXT-1 and EXT-2 gene mutations in chromosomes 8 and 11 implicated.[2] Only 1–4% of these tumors involve the spine. Occurrence in facial bones is also a rarity.[3] As per the literature, less than 35 cases of vertebral exostosis in the thoracic pedicle have been described. Osteochondromas are thought to originate from within the periosteum as small cartilaginous nodules. The bony mass usually consists of a stalk with endochondral ossification of a growing cartilaginous cap. The growth of these tumors usually stops with the attainment of the skeletal maturity. These tumors, if they do occur in the spine, usually involve the posterior elements.[4] With the growth of the tumor, the already narrow spinal canal gets invaded causing compression of the spinal cord, as in this case. This can be catastrophic, causing weakness and numbness, in which case it will require a surgical removal. With multiple osteochondromas, myelopathy is predominantly seen.[5] They are sometimes missed on the plain radiographs, unless it is of a large size, and MRI/CT scan maybe required to see the lesion.On x-ray Osteochondromas should appear with well defined borders, however they are clearly demarcated if the lesion is large enough radiologically.[1],[2] An MDCT is extremely useful to evaluate the size, characteristics, and the site of the osteochondroma. The most commonly reported location of osteochondroma is over the lamina in the upper thoracic or the cervical regions.[6],[7],[8] The extent of the cord compression can be visualized with the help of an MRI; in addition, MRI is also useful in diagnosing and planning the surgery.[4],[5] Postoperatively, a biopsy of the resected lesion is required for confirmation. Differential diagnoses for osteochondromas, depending on the site, include osteoma, synovial cysts, chondroblastoma, benign osteoblastoma, myxoma, fibro-osteoma, fibrous cell dysplasia, fibrosarcoma, and chondrosarcoma.[9] Due to the shared characteristics, a thorough clinical, radiological, and histological examination is important.
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.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
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