Consequences of Acute Presentations of Functional Neurological Disorders in Neuro‐Oncology Patients: Case Series and Systematic Review

Introduction New neurological symptoms in neuro‐oncology patients are usually attributed to the tumor or its treatment. A diagnosis of functional neurological disorder (FND) is often only considered when investigations do not reveal a cause and medical management fails. The consequences to neuro‐oncology patients of comorbid FND have not been elaborated. Methods We performed a single‐center retrospective case study of adult neuro‐oncology patients with an intracranial tumor who presented acutely with FND and required expedited investigations. Data recorded were tumor type, investigations, adverse life events, medical interventions, and outcomes. This was combined with a systematic literature review. Results Ten patients met our study criteria. Six had functional seizures, two had functional hemiparesis, and two had functional speech disorders. FND symptoms started prior to tumor diagnosis in three patients; between diagnosis and tumor treatment in three patients; and after treatment commenced in four patients. Two patients were thrombolyzed for a presumed stroke. Three patients had either their tumor surgery or chemoradiotherapy delayed. Diagnosis and management of FND enabled tumor treatment to restart. The systematic review identified 43 patients. Thirty‐nine had functional seizures, and four had motor FND. All FNDs except one started after tumor treatment commenced. Conclusion Acute FND can occur at any stage of a brain tumor illness. The FND may lead to unnecessary medical interventions and can disrupt tumor treatment. Although acute FND improved with diagnosis and explanation, many neuro‐oncology patients require a multidisciplinary tumor–FND pathway to manage acute FND and avoid delays to tumor treatment.