Objective: Pediatric neuroimmunology is a rapidly changing field with many unknowns. Functional neurological symptoms are also poorly understood in children, and often considered only when medical causes are ruled out. This case highlights the need for collaboration between neuropsychologists and neurologists when evaluating patients with unusual presentations, suspected rare disorders, and possible psychological symptom exacerbation. Method: Kate is a 12-year-old Caucasian female with a two-year history of sudden-onset unusual neurological symptoms, most prominently a high-pitched voice and stereotypically feminine mannerisms, characterized by her family as “a Disney princess.” The family reported cognitive impairments in processing speed and memory. Testing of blood and cerebrospinal fluid revealed mildly elevated levels of interleukin 6 and 8 as well as S100B protein of unknown significance. Parents reported symptom improvement from immunological treatments. Results: Neuropsychology was consulted to assess neurocognitive functioning before and after intravenous immunoglobulin (IVIg) and evaluate psychological factors. Initial evaluation revealed slow processing speed and anxiety by self and parent rating. Two months later, evaluation revealed worse performance on verbal list-learning and equivocal performance on processing speed tasks. Self-rating of anxiety was worse. However, Kate and her family reported improved functioning. One year later, Kate had completed IVIg treatments and the family had made multiple changes to reduce stress. Kate and her family reported significant symptom improvement. Her “princess” presentation was remarkably less evident. Conclusion: In this case, neuropsychology helped inform treatment and provide information regarding a possible functional etiology. Close collaboration between disciplines resulted in an excellent outcome for Kate and her family.