B. Neuroschistosomiasis
Although listeriosis is a major cause of rhombencephalitis, the CSF typically does not show eosinophilic meningoencephalitis, and the patient’s blood and CSF cultures were sterile. Beyond listeriosis, other infections (herpesvirus infections and tuberculosis) and autoimmune diseases (Behçet disease, systemic lupus erythematosus, vasculitis, demyelinating diseases, and paraneoplastic syndromes) may cause rhombencephalitis.1 The patient presented with a nodular lesion with an heterogenous, multinodular, contrast-enhancing pattern consistent with a granulomatous disease (eg, infection by mycobacteria, fungi, parasite, or even sarcoidosis).2,3
The differential diagnosis is narrowed largely by the CSF characteristics. Eosinophilic meningoencephalitis is defined as the presence of more than 10 eosinophils/mm3 in CSF and/or eosinophils accounting for more than 10% of cerebrospinal leukocytes.4 The most common cause of eosinophilic meningoencephalitis is invasion of the central nervous system by helminthic parasites, such as Angiostrongylus cantonensis, Gnathostoma species, Schistosoma mansoni, and Taenia solium.5 Eosinophilic granulomatosis with polyangiitis may present eosinophilia and neuromyelitis-optica spectrum disorders may present some eosinophils in the CSF, but we would not expect sufficient eosinophils to fulfill the definition of eosinophilic meningoencephalitis in these diseases.