Spinal Lesions: A Dilemma Despite All Diagnostics

When a spinal lesion is encountered, pyogenic spondylodiscitis (bacterial), tuberculosis (TB) of the spine, and malignancy are close differential diagnosis that have to be considered. A combination of clinical history, examination findings, imaging modalities, blood investigations and histopathological examination should be used to conclusively differentiate between them. A 58 year old lady complained of pain in lower back for two months. She did not have any history of fever, weight loss or loss of appetite. She was diagnosed to have breast carcinoma seven months earlier, for which she had undergone left modified radical mastectomy six months back, and completed five cycles of chemotherapy two months back. On examination, she had tenderness in L5-S1 region. There were no neurological deficits. Erythrocyte sedimentation rate and C-reactive protein were found to be elevated. Blood culture showed no growth. Radiographs of the spine only showed spondylolisthesis of L5-S1. Radiograph of the chest showed an isolated, irregular, patchy lesion in the upper lobe of the right lung. Magnetic Resonance imaging (MRI) of spine showed a T2 hypo intense lesion involving the L5, S1 vertebral bodies and L5-S1 intervertebral disc. Positron Emission Tomography (PET) showed increased metabolic activity in the upper lobe of right lung and pre-vertebral region of L5-S1. Brochoalveolar lavage specimen was found to be negative for acid fast bacilli staining, negative for GeneXpert test for TB, and showed no growth on culture. We then performed a percutaneous biopsy of the L5-S1 lesion under intravenous sedation. The tissue specimen showed no growth on culture. The histopathological examination mild increase in lymphocytes and plasma cells suggestive of a reactive marrow. No evidence of granuloma or malignancy were present. The patient was then started on broad spectrum antibiotic, which was continued for 1 month. Patient showed symptomatic improvement within 15 days of initiation of antibiotics. She was followed up for a period of 2 years and found to have no recurrence of symptoms. Thus, in rare instances like our case, differentiating between tuberculosis of the spine, pyogenic spondylodiscitis can pose a diagnostic challenge despite all investigations.