An Old Foe in a New Spot – TB in the Sella

Introduction: Central Nervous System (CNS) infection with Mycobacterium tuberculosis (MTB) is rare in the immunocompetent child. Tuberculomas are a form of CNS disease that, in isolation, may have focal neurological findings. When tuberculomas occur in the setting of meningitis, they are usually subclinical. We present a case of presumed tuberculosis (TB) meningitis with a suprasellar tuberculoma, manifesting as a space-occupying lesion.

Case Description: A 17-year-old healthy, vaccinated male presented with four months of fevers, fatigue, headaches, and weight loss, and two days of emesis and neck pain. He was born in and resides in Southern California and traveled to Mexico five years earlier. His sister had a history of latent TB. Exam showed a thin male with shotty cervical lymphadenopathy, clear lungs and a normal neurologic exam. Cerebrospinal fluid (CSF) analysis revealed a white blood cell count of 5960 cells/μL with neutrophil predominance, protein 492 mg/dL and glucose 11 mg/dL. An MRI brain showed a rim-enhancing sellar lesion, concerning for craniopharyngioma versus infectious mass. He was treated empirically with antibiotics and rifampin, isoniazid, pyrazinamide, and levofloxacin (RIPL). Infectious workup was negative for bacteria, fungi, and mycobacteria. Sputum MTB PCR, serum interferon-gamma release assay, and chest X-ray were negative. Workup for immune deficiency was normal. Additional lab-work revealed pan-hypopituitarism and he was treated with vasopressin, hydrocortisone, and levothyroxine. He continued on RIPL and repeat CSF and MRI at two weeks showed resolution of meningitis and decrease in mass size.

Discussion: Diagnosis of CNS TB is difficult, presenting a diagnostic conundrum for the inpatient team. Patients with TB meningitis may be acutely ill with neurological sequelae, their CSF profile typically shows lymphocytic predominance, and MRI usually demonstrates basilar enhancement. Our patient’s endocrinopathies in the setting of a sellar mass were classic for craniopharyngioma, but radiographic findings appeared more cystic, without the typical calcifications, pointing towards an infectious etiology. Biopsy was deferred due to risk; furthermore, he clinically improved on RIPL therapy with reduction in mass size. Ultimately his mass was most consistent with a tuberculoma. Tuberculomas are aggregates of immunologic and inflammatory cells and can be discovered incidentally with TB meningitis or manifest as CNS tumors. Discrete, ring-enhancing lesions are typically seen on imaging. In endemic TB regions, concurrent tuberculomas with meningitis can be seen in up to 39% of cases (Anuradha 2011) but is rarely encountered in North America. After prolonged treatment with anti-Mycobacterial therapy, our patient improved significantly with continued mass reduction and restoration of pituitary function.

Conclusion: Meningitis is a rare extra-pulmonary manifestation of TB. Concurrent tuberculomas may manifest as space occupying lesions, often requiring a high index of suspicion for diagnosis. CNS tuberculomas are typically in the frontoparietal regions, but in this case found in the suprasellar space causing pituitary dysfunction and endocrinopathies.