Meningoencephalomyelitis as the initial symptom of a brain tumour mimicking encephalitis due to herpes simplex virus: a case report

Meningoencephalomyelitis can be due to a number of treatable causes. A tumoural aetiology is rare and they are generally malignant tumours with an ominous prognosis. We report a case of meningoencephalomyelitis that initially presented as encephalitis due to herpes simplex virus (HSV) and which was finally seen to be an anaplastic oligoastrocytoma. We describe the case of a 68-year-old male with a history of just strong low back pain during the previous month, who was admitted to hospital because of progressive clinical symptoms involving cognitive impairment and myoclonias. The polymerase chain reaction for the cerebrospinal fluid was positive for HSV and magnetic resonance imaging revealed diffuse compromise of right temporal lobe, the spinal cord and the cervical meninges. The progressive deterioration of the patient despite treatment with acyclovir, anti-tuberculosis agents and with corticoids made it necessary to perform a biopsy study of the cervical meninges, the results of which suggested non-specific macromonocytic meningoencephalitis. The patient's condition continued to deteriorate until he died. The post-mortem examination revealed a grade III oligoastrocytoma in both temporal lobes, which had extended into the adjacent subarachnoid space and the cerebral and cervical leptomeninges. Non-specific symptoms of low back pain can conceal a brain tumour. Attention is drawn to how infrequently it manifests clinically and in imaging studies as meningoencephalomyelitis due to direct tumoural invasion. This should be considered as a possibility when faced with a slowly progressing clinical picture that, despite the initial suspicion of encephalitis due to HSV, does not respond to the usual treatment.