Medulloblastoma masquerading as tuberculous meningitis in a pediatric patient

Small round blue cell tumors are a heterogeneous group of aggressive pediatric neoplasms that can radiologically and clinically mimic infectious or inflammatory conditions, including tuberculous meningitis (TBM). Differentiating between these entities is crucial, as delays in diagnosis may significantly affect outcomes.

An 8-year-old previously healthy boy presented with acute lower extremity weakness, inability to ambulate, and urinary retention following a recent urinary tract infection. Neurological examination revealed symmetric distal weakness and areflexia. Cerebrospinal fluid analysis showed markedly elevated protein levels without pleocytosis, consistent with albuminocytologic dissociation, and Guillain-Barré syndrome was diagnosed. Intravenous immunoglobulin therapy was initiated; however, no clinical improvement was observed. During hospitalization, the patient developed seizures and signs of increased intracranial pressure. Craniospinal magnetic resonance imaging revealed hydrocephalus and multiple contrast-enhancing lesions involving the suprasellar region, brainstem, and cerebral hemispheres. Despite extensive infectious and inflammatory workup, no alternative diagnosis was identified initially. Brain biopsy ultimately demonstrated a CD56- and synaptophysin-positive small round blue cell tumor, consistent with medulloblastoma. This case highlights a rare presentation of medulloblastoma mimicking TBM and underscores the importance of reconsidering the diagnosis in patients with atypical features or poor response to standard therapy.

This case demonstrates that the extremely rare leptomeningeal spread of medulloblastoma can clinically and radiologically mimic TBM, posing a significant diagnostic challenge in pediatrics. In the absence of systemic signs of tuberculosis, lack of response to treatment, and the presence of progressive neuroimaging abnormalities, the diagnosis should be reconsidered. Early histopathological confirmation is essential to ensure the timely initiation of oncological treatment.