Multifocal skeletal tuberculosis.

Abstract: Multifocal skeletal tuberculosis is defined as osteoarticular lesions that occur simultaneously at two or more locations. We present radiologic findings in two cases of multifocal osteoarticular tuberculosis. Differential diagnoses of such lesions, based on different radiologic modalities, can include metastatic disease, eosinophilic granuloma, or lymphoma. Since tuberculosis can be present in multiple sites, especially in patients from areas where tuberculosis is endemic, it is essential to avoid a delay in diagnosis.

Key Words: magnetic resonance imaging, multifocal, skeletal, tuberculosis

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Multifocal skeletal tuberculosis is defined as osteoarticular lesions that occur simultaneously at two or more locations in the skeletal system. Multifocal skeletal tuberculosis lesions are very rare, and radiological appearance may simulate primary or metastatic disease. (1) We report the plain film, computed tomography (CT) and magnetic resonance imaging (MRI) findings of two cases of multifocal skeletal tuberculosis and provide a brief discussion of these radiologic findings.

Case Reports

Patient 1

A 24-year-old male presented with a complaint of neck pain and stiffness of 2 to 3 months' duration. On physical examination there was tenderness with palpation over the cervical spinal area. Laboratory results were within normal limits. A cervical radiograph revealed a destructive lesion, pathologic fracture, and anterior subluxation of the C2 vertebral body (Fig. 1A). A CT scan of the cervical region with intravenous contrast medium showed narrowing of the atlantoaxial articular space, atlantoaxial articular surface irregularities, and destructive lesion in the corpus and inferior part of the dens of the axis. CT scan also demonstrated a soft tissue mass in the retropharyngeal area at the level of the first and second cervical vertebrae. MRI with contrast media revealed a soft tissue mass at the level of C1 and C2 which had destroyed the corpus of the C2 vertebra and intervertebral disc. The soft tissue mass was extending into the anterior subarachnoid space (Fig. 1B). Thorax CT examination demonstrated multiple destructive soft-tissue lesions in the posterior part of the left fifth rib (Fig. 1C), and costovertebral junction of the right eighth rib (Fig. 1D). There was no pulmonary pathology.

The soft tissue mass at the level of C1 and C2 was removed surgically via transoral approach. Histopathological examination revealed a necrotizing granulomatous infection. A diagnosis of Pott disease and tuberculous osteomyelitis was made, the patient was put on antituberculosis therapy, and his neck was stabilized with a cervical halo. After two months of follow-up, the multiple costal lesions and the soft tissue lesion in the cervical area showed nearly total healing with minimal kyphotic deformity.

Patient 2

A 53-year-old female was admitted to our hospital for bilateral severe lower extremity weakness lasting for 2 weeks, and back pain complaints that had lasted for 2 years. On neurologic examination, there were bilateral motor dysfunction in the lower extremities, bilateral hypoesthesia below the level of the T9 and T10 vertebrae, bilateral positive Babinski reflex, and hypoactive tendon reflexes. MRI of the lumbar vertebrae demonstrated a soft tissue mass at the level of the L4 vertebra corpus that caused compression on the dural sac and right L5 nerve root (Fig. 2A). There was also a soft tissue mass at the level of the S1 through S3 vertebrae which extended to the S2 and S3 neural foraminae and right sacroiliac joint. Dorsal MRI examination revealed pathologic signal changes in the T8 and T9 vertebrae bodies and intervertebral disc with retropulsion. There was an accompanying anterior epidural soft tissue mass, making an external compression on the dorsal spinal cord, and causing myelopathic changes (Fig. 2B). There was also right sacroiliac joint erosion and abscess formation in the right psoas and iliopsoas muscles (Fig. 2C).

The combined radiographic appearance of dorsal vertebral changes, psoas abscess, and sacral vertebral pathologies was considered to be a strong indicator of multifocal tuberculous infection. The patient was given antituberculous therapy. At a 3-month follow-up there was regression in the findings of spondylodiscitis at the dorsal and lumbar levels.

Discussion

Skeletal tuberculosis is thought to occur secondary to lymphohematogenous dissemination to the skeleton at the time of initial pulmonary infection. (1) There may be no radiographic evidence of pulmonary involvement in about 50% of patients. (2) Clinical and radiographic presentation of skeletal tuberculosis in patients from endemic areas differs from that of individuals from nonendemic areas. (3) Patients from endemic areas present with a higher incidence of multifocal skeletal involvement. Radiographic features may present as periosteal reaction, bone sclerosis, and severe bone destruction. The profile from nonendemic areas is of an older patient, usually with a debilitating underlying disease; lesions are usually solitary, osteolytic, and involving the axial skeleton, thoracolumbar vertebral bodies, and hips. (3) The two cases in our report were from endemic areas and had multiple skeletal lesions.

The spine is the most common site of involvement, accounting for more than 40 to 60% of all cases of skeletal tuberculosis. Lumbar and thoracic regions are more often involved, whereas the incidence of cervical involvement is 2 to 3%. (4) In one of our cases (patient 1), there was upper cervical spine involvement with a soft tissue component extending to the anterior subarachnoid space. In the other case, there were multiple lesions in dorsal, lumbar, and sacral areas, all with bone destruction and accompanied by adjacent soft tissue masses.

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The rib is involved in between 0 and 5% of osteoarticular tuberculosis cases, and it is the most commonly involved site in extrapulmonary tuberculosis in heroin-addicted patients. (1) Multifocal skeletal tuberculosis lesions have also been increasingly reported in heroin addicts. In patient I there were multiple rib involvements, such as bone destruction and associated extrapleural soft tissue masses, and neither of our patients were heroin abusers.

The radiographic appearance of osteoarticular tuberculosis can mimic metastatic tumors or some primary osseous lesions, such as eosinophilic granuloma, especially if multiple destructive lesions are present. (5) To prevent a delay in diagnosis, multifocal tuberculous osteomyelitis should be considered in the differential diagnosis of multiple destructive skeletal lesions, especially in patients from endemic areas.

Radiological imaging methods are essential in the diagnosis and follow-up of patients with tuberculous osteomyelitis. Conventional radiography should be the first diagnostic method employed. Radiographically, tuberculous lesions are mostly osteolytic, but sclerosis may also be seen. Patients may also present with pathologic fractures. Lesions may not be detected radiographically, particularly early in the process. (6,7) For these silent lesions, CT or bone scintigraphy could be helpful. Bone scans sometimes cannot differentiate between metastasis and tuberculosis, however, due to the purely lytic and avascular nature of the lesions in the early phase of the disease. (6)

CT is helpful in detecting bone destruction and adjacent soft tissue masses. CT can reveal osteolytic expansive lesions with varying degrees of bone destruction and accompanying low-density soft tissue masses with peripheral rim enhancement. (7) CT can also be a helpful radiologic modality in percutaneous biopsy or abcess drainage.

MRI is useful in showing the extent of the disease, particularly in spinal lesions. (8) MRI is superior to plain radiographs in showing the extent of extraskeletal involvement, particularly in the case of compromise of the vertebral canal and the epidural space. (3) Both CT and MRI can be used in patient follow-up to evaluate responses to therapy. (8)

Conclusion

We presented two cases of multifocal osteoarticular tuberculous lesions. Radiographic appearance of skeletal lesions simulate metastatic disease, eosinophilic granuloma, or lymphoma. To avoid a delay in diagnosis, tuberculosis should be kept in mind, since tuberculosis can present in multiple sites, particularly in patients from regions where tuberculosis is endemic.

Accepted September 30, 2003.

References

1. Muradali D. Gold WL, Vellend H, et al. Multifocal osteoarticular tuberculosis: report of four cases and review of management. Clin Infect Dis 1993;17:204-209.

2. Reider HL, Snider DE Jr. Cauthen GM. Extrapulmonary tuberculosis in the United States. Am Rev Respir Dis 1990;141:347-351.

3. Alvarez S, McCabe WR. Extrapulmonary tuberculosis revisited: a review of experience at Boston City and other hospitals. Medicine 1984;63:25-55.

4. Weaver P, Lifeso RM. The radiological diagnosis of tuberculosis of the adult spine. Skeletal Radiol 1984;12:178-186.

5. Chang DS, Rafii M, McGuinness G, et al. Primary multifocal tuberculous osteomyelitis with involvement of the ribs. Skeletal Radiol 1998;27:641-645.

6. Wiebe ER, Elwood RK. Tuberculosis of the ribs- a report of three cases. Respir Med 1991;85:251-253.

7. Lee G, Im JG, Kim JS, et al. Tuberculosis of the ribs: CT appearance. J Comput Assist Tomogr 1993;3:363-366.

8. Thrush A, Enzmann D. MR imaging of infectious spondylitis. Am J Neuroradiol 1990;11:1171-1180.

RELATED ARTICLE: Key Points

* Clinical and radiographic presentations of skeletal tuberculosis in patients from endemic areas differ from those in individuals from non-endemic areas.

* The radiographic appearance of osteoarticular tuberculosis can mimic metastatic tumors or primary osseous lesions such as eosinophilic granuloma, especially if multiple destructive lesions are present.

* Magnetic resonance imaging is superior to plain radiographs in showing the extent of extraskeletal involvement, particularly in the case of compromise of the vertebral canal and the epidural space.

Mehmet Halit Yilmaz, MD, Fatih Kantarci, MD, Ismail Mihmanli, MD, and Kaya Kanberoglu, MD

From the Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.

Reprint requests to Kaya Kanberoglu, MD, Professor of Radiology, Istanbul University, Cerrahpasa Medical Faculty, Department of Radiology, 34300-Istanbul, Turkey. Email: [e-mail]