Magnetic resonance spectroscopy (MRS) as an aid to diagnose a ruptured neurenteric cyst mimicking infectious meningitis- a case report

Abstract

Introduction Neurenteric cysts are rare neoplasms from aberrant developmental endodermal tissues linked to the notochord that form later in life as midline masses, mainly in the brainstem and spinal cord. Few case reports documented meningitis associated with these cysts, but none describe how MRS can aid in diagnosing this rare condition when it overlaps clinically with infectious meningitis. Case presentation We report a case of a 22-year-old male with a family exposure to tuberculosis and multiple male sexual partners, presented with a two-week history of fever, headache, neck pain, progressive leg numbness, progressing to paralysis, alongside mental slowing, vision deterioration, and focal seizures a few days before admission. He had normal blood pressure and tachycardia but remained oriented and responsive. Physical examination revealed no light perception, sluggish pupillary reaction, cranial nerve abnormalities on the right side, reduced reflexes, paraplegia, and nuchal rigidity. Initial imaging showed hydrocephalus, basal enhancement, and right cerebellopontine mass, thus managed as tuberculous meningitis with tuberculoma and underwent surgery. The infectious work-up was negative for both cerebrospinal fluid and blood. Magnetic resonance spectroscopy (MRS) showed NAA-like peaks, and the absence of lipid-lactate peaks was consistent with neurenteric cysts. Further surgery was no longer feasible as the patient deteriorated with sepsis and succumbed to brainstem compression. Conclusion This case underscores the importance of knowing rare and atypical presentations, such as ruptured neurenteric cysts causing chemical meningitis presenting as more common infectious meningitis and the utility of MRS in helping narrow down the differential diagnoses and clinching the diagnosis.