Anti-Ma1/Ma2 paraneoplastic neurological syndrome associated with malignant mesothelioma: a case study

Anti-Ma1/Ma2 paraneoplastic neurological syndromes (PNS) are rare immune-mediated disorders classically associated with testicular germ cell tumours but increasingly recognised in a broader range of malignancies.

We report a 74-year-old left-handed man who presented with progressive gait ataxia. MRI of the brain showed T2 hyperintensity in the right amygdala and hippocampus, as well as in the left caudate head. Serum and cerebrospinal fluid tested positive for anti-Ma1/Ma2 antibodies. Despite extensive screening, no malignancy was identified.

Neurological deficits worsened over 2 months, including worsening gait, ataxia, opsoclonus and left arm weakness. High-dose corticosteroids, intravenous immunoglobulin, mycophenolate and rituximab led to modest clinical improvement. 4 months later, the patient re-presented with insidious respiratory distress due to a right pleural effusion. Pleural biopsy confirmed mesothelioma. Anti-Ma1/Ma2 PNS linked to mesothelioma are rare but have been reported.

For this rare association, previous few cases described neurological symptoms emerging months to years after a mesothelioma diagnosis, while ours is the first to report symptoms preceding diagnosis. Early immunosuppression can provide temporary clinical benefit. A more sustained benefit requires identification and treatment of the underlying malignancy. This case underscores the importance of ongoing surveillance for malignancy in patients with PNS.