Tuberculosis of the axis in a patient with systemic sarcoidosis: Technique of posterior open biopsy of the dens: Case report

OBJECTIVE AND IMPORTANCE: This case report illustrates the importance of obtaining tissue from a destructive lesion of the dens in a patient with systemic sarcoidosis. Although sarcoidosis can involve the axial skeleton, tissue obtained at the time of C1-C2 fusion demonstrated unsuspected pathological features, which dramatically altered the subsequent medical treatment. The technique of open posterior biopsy of the dens is illustrated, and the advantages of the approach are discussed. CLINICAL PRESENTATION: A 40-year-old woman with systemic sarcoidosis developed neck pain and atlantoaxial instability. Imaging revealed multiple thoracic and cervical vertebral abnormalities, including a destructive enhancing lesion involving the base of the dens. INTERVENTION: At the time of posterior C1-C2 fusion, we elected to perform an open biopsy of the base of the dens. A 16-gauge biopsy needle was introduced along the medial portion of the left C2 pars, aiming medially toward the base of the odontoid process. This procedure was performed under direct observation, with fluoroscopic guidance. The biopsy specimen contained caseating granulomas, and cultures were positive for Mycobacterium tuberculosis. CONCLUSION: The unusual presentation, the technique, and the importance of obtaining tissue to confirm the diagnosis of tuberculous involvement of the dens are emphasized. The relationship between sarcoidosis and tuberculosis reported in the literature is reviewed. In the current case, cell wall-positive tuberculous bacteria were cultured, confirming the presence of two separate diseases in the same patient.