
==== Front
Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00716-7
10.1016/j.radcr.2024.07.129
Case Report
Unveiling diagnostic challenges: A case report of noncontagious vertebral involvement in spinal tuberculosis mimicking metastasis
Dahal Prajwal MD meprajwal7@gmail.com
a⁎
Bastola Shova MD b
Maharjan Santosh MD a
Adhikari Govinda MD a
Parajuli Sabina MBBS c
a Consultant Radiologist, Department of Radiology and Imaging, Grande International Hospital, Kathmandu, Nepal
b Consultant Pathologist, Department of Radiology and Imaging, Grande International Hospital, Kathmandu, Nepal
c Department of Pathology, Bir hospital, Kathmandu, Nepal
⁎ Corresponding author. meprajwal7@gmail.com
22 8 2024
11 2024
22 8 2024
19 11 51335138
18 5 2024
20 7 2024
22 7 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Spinal tuberculosis usually involves intervertebral disc, pardiscal vertebra and has associated perivertebral collection. Involvement of vertebral body including the posterior element, noncontagious vertebral involvement and sparing of intervertebral discs is typical of metastasis. Index case, a 19 years old Nepali patient presented to our hospital with complaints of severe backache. Blood and urine investigations were normal except elevated erythrocyte sedimentation rate and C- reactive protein. A contrast enhanced computed tomography (CT) showed lytic lesions in clivus, C7, T10, and L3 vertebral bodies with involvement of right sided posterior elements of C7 and T10. Mild surrounding soft tissue was seen. Contrast enhanced MRI showed similar findings and also lesions in S1 and right sacral ala. Possibility of metastatic lesion was considered over tuberculosis. A CT guided biopsy from right pedicle of T10 vertebra confirmed tubercular etiology.

Keywords

Biopsy
Clivus
Intervertebral disc
Metastasis
Tuberculosis
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pmcBackground

Tuberculosis (TB), caused by mycobacterium tuberculosis, is prevalent in underprivileged regions of the world. Due to global migration, the incidence of TB infection is increasing in developed countries as well. According to the World Health Organization (WHO), one-third of the world's population, which is 2 billion people, is infected with TB [1]. About 0.6 million people died in South Asia because of TB [2]. Skeletal tuberculosis accounts for 5% of all TB infections, with spinal tuberculosis making up 50% of all skeletal tuberculosis cases [1].

Spinal tuberculosis can present in intramedullary, intradural extramedullary, and extradural forms [2]. The majority of spinal TB infections are of the extradural form [3]. Typical spinal tuberculosis involves the disc and contiguous paradiscal vertebrae, with the posterior elements usually spared and paravertebral collections present [4]. The contiguous vertebral involvement in spinal tuberculosis is explained by the fact that a vertebral artery supplies 2 adjacent vertebrae, and skeletal tuberculosis is caused by hematogenous spread [5].

However, atypical presentations are not uncommon. Involvement of noncontiguous vertebrae, posterior elements, sparing of intervertebral discs, and lytic lesions in vertebrae are findings typical of metastasis [6]. Here, we present an atypical case of spinal tuberculosis which shows features similar to metastasis. Atypical presentations can result in delayed diagnosis and sometimes misdiagnosis.

Case presentation

A 17-year-old Nepali male with no known comorbidities presented with severe, dull aching back pain for 1 week, worsening at night and with movement. There were no constitutional symptoms like fever, cough, night sweats, weight loss and loss of appetite. The patient denies any history of close contacts with TB. He was given BCG vaccine during childhood. Physical and systemic examinations were normal. Mild tenderness was present in bilateral paraspinal region in lower dorsal spine. Respiratory and cardiovascular examination was normal. The power of bilateral leg was 6/6. No sensory deficit was present. Blood investigations showed normal hemoglobin level (13.8 gm/dL). The total leucocyte count was 10,000/mm3. Differential leucocyte count showed 65% neutrophils and 25% lymphocytes. The elevated erythrocyte sedimentation rate and C-reactive protein levels were elevated with values 13.6 mg/L and 88 mm/hour respectively. Viral markers for HIV were negative. Plain radiograph of chest revealed no obvious abnormality. Ultrasonography of abdomen also revealed no obvious abnormality. Contrast-enhanced CT of the chest and abdomen revealed lytic lesions in the clivus, C7, T10, and L3 vertebrae (Figs. 1A and B), with mild perivertebral soft tissue involvement, mainly at C7, T10 and L3 levels. Right-sided pedicle and lamina involvement were noted in C7 and T10 vertebrae. MRI showed similar findings with additional lesions in the S1 vertebra and ala of the right sacrum (Figs. 2A-D). Contrast enhanced T1 images showed similar findings with enhancement of involved vertebrae and perivertebral soft tissue (Figs. 3A-F). Initial impression of metastatic disease was made. Biopsy was advised for confirmation. A CT-guided biopsy from the right pedicle of T10 vertebra (Fig. 4) revealed granulomas (Fig. 5A) and acid-fast bacilli (Fig. 5B), indicating TB infection. Antitubercular therapy (ATT) was started. After 3 months of ATT, the patient was pain-free and doing well, with follow-up imaging planned post-therapy.Fig. 1 CT images of the spine. (A) Sagittal image of cervical and upper dorsal spine, showing lytic lesions in the clivus, C1, and C7. (B) Sagittal image of lower dorsal and lumbosacral spine, showing lytic lesions in the right T10 vertebra and L3 vertebral body.

Fig 1:

Fig. 2 Short tau inversion recovery (STIR) images of the spine and sacrum. (A) Sagittal image of cervical and upper dorsal spine, showing high signal in the clivus, C1, and C7, including C7′s posterior elements. (B) Sagittal image of lower dorsal and lumbosacral spine, showing high signal in the right posterior element of T10 and the body of L3. (C) High signal in the ala of the right sacrum. (D) Coronal image of atlanto-axial joint and cervical spine, showing high signal in the C1 vertebra.

Fig 2:

Fig. 3 Postcontrast fat-saturated T1 images of the spine. (A-C) Sagittal images of the cervical and upper dorsal spine, lower dorsal spine, and lumbosacral spine, respectively. (A) Enhancement of the clivus, C1, and C7, including C7′s posterior element, with mild soft tissue enhancement in the prevertebral and epidural space at C7. (B) Enhancement of the right pedicle of T10, the body of L3, and the body of S1. (D-F) Axial images at the C7, T10, and L3 levels, showing enhancement in the vertebrae and perivertebral soft tissue, including the posterior elements.

Fig 3:

Fig. 4 Image showing CT guided biopsy from right pedicle of T10 vertebra. A needle is seen in right pedicle of the vertebra.

Fig 4:

Fig. 5 (A) Cytology of the material shows aggregates of well-defined epithelioid cells surrounded by lymphocytes forming a granuloma. Figure 5B shows acid fast bacillus in Ziehl-Neelson stain (black arrow).

Fig 5

Discussion

Tuberculosis is a deadly infection that affects virtually all organ systems. It primarily infects the lungs through droplet inhalation, from where the bacterium spreads hematogeneously to extrapulmonary sites [2]. The hematogenous spread usually occurs through the arterial route, and less often through the venous route. Typically, tubercular infection causes spondylodiscitis, in which the intervertebral disc, paradiscal vertebrae, and perivertebral soft tissue are involved [1]. The most common site is the dorsal spine, followed by the lumbar, cervical, and sacral spine [5]. The picture of typical spinal tuberculosis is explained by the arterial route of hematogenous spread. An artery supplies 2 consecutive vertebrae; when 2 contiguous vertebrae are involved, the intervertebral disc loses its nutritional support, allowing the infection to spread [7].

Atypical forms of spinal tuberculosis involve a single vertebral body, noncontiguous vertebral bodies, neural arch tuberculosis, extradural collection without involvement of vertebrae, and spinal cord involvement [8]. The atypical picture of spinal tuberculosis can be explained by the venous route of spread of the disease [9]. The posterior external venous plexus of vertebral veins is located on the posterior surface of the lamina and the spinous, transverse, and articular processes. This plexus anastomoses with other vertebral plexuses, constituting the final pathway for the infection to reach the neural arch. Vertebral body involvement without disc involvement is the most common form of atypical spinal tuberculosis [7]. The atypical features of spinal tuberculosis described above are also seen in metastatic lesions. However, perivertebral and epidural collections are not typical of metastasis. As a rule of thumb, if there is involvement of the intervertebral disc, it is not metastasis [10]. Metastasis to the vertebral body results in its expansion and arcing of the posterior border of the vertebral body and spinal canal narrowing [10]. The spread of malignancy to the vertebra also occurs through the posterior external venous plexus. Thus, the picture of spinal metastasis is similar to that of atypical spinal tuberculosis.

It is very difficult to differentiate metastasis from atypical spinal tuberculosis using imaging alone. We advise giving a differential diagnosis rather than a definitive diagnosis if such imaging findings are seen, and confirming with a biopsy.

Conclusion

Tubercular infections are common in underprivileged regions and are increasing in developed countries. Spinal TB can present atypically, with noncontiguous vertebrae involvement, posterior element involvement, and intervertebral disc sparing, mimicking metastasis. Biopsy is advised for accurate diagnosis rather than relying solely on imaging.

Availability of data and material

The data and material are not available in public repository since this is a case report.

Ethics approval and consent to participate

Ethical approval is not required for this manuscript since this is a case report. Consent to participate was obtained from the patient. A copy of the consent form is available for review by the Editor of this journal.

Consent for publication

Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient. A copy of the consent form is available for review by the Editor of this journal.

Author contributions

Prajwal Dahal: Conceptualize, manuscript writing, Shova Bastola: Pathology work up, Santosh Maharjan: Literature search, Govinda Adhikari: Manuscript writing, Sabina Parajuli: Manuscript writing.

Patient consent

Informed written consent was obtained from the patient for publication of the case including images.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments: No acknowledgement to be made.
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