Opsoclonus-myoclonus-ataxia syndrome as a complication of pembrolizumab treatment in an adult patient (a case report and literature review)

Abstract

Background. Opsoclonus-myoclonus-ataxia syndrome (OMAS) in adults is an extremely rare condition, often leading to rapidly deteriorated neurological performance. The majority of published cases are considered as being of post-infectious, paraneoplastic or idiopathic origin. However, there have been reported few OMAS cases developed after administration of check-point inhibitors used in various oncological conditions. In the last decade, the widespread use of immunotherapy in oncology has led to rise in immune-related adverse events, including diverse neurological toxicities.Objective: to evaluate an opportunity of OMAS-triggering PD-1 treatment.Material and methods. We present the case report of a subacute OMAS onset in an elderly man after continuous administration of pembrolizumab as a first line treatment in bronchial squamous cell carcinoma. The study was conducted in accordance with the Helsinki Declaration. We also review the main OMAS clinical features, pathogenesis and immunological mechanisms in adults along with potential diagnostic and management strategies.Results. The development of severe OMAS clinical picture during immunotherapy required the withdrawal of targeted treatment, which in combination with glucocorticoids led to a prominent regression of neurological deficit. After a thorough clinical investigation, infectious and organic factors were excluded, allowing for proposal of immunotherapy-triggered OMAS etiology in the patient.Conclusion. Discontinuation of immunotherapy may be a justified means for OMAS clinical features in adult patients with verified oncological condition undergoing treatment with check-point inhibitors (considering all other etiologies are ruled out).