A-84 Interdisciplinary Collaboration: Neuropsychology’s Role in Elucidating Neurocognitive Symptoms in a Patient with Arachnoid Cyst

Objective Arachnoid cysts (ACs) are typically cerebrospinal fluid-filled abnormalities that occur within the central nervous system. ACs are uncommon (prevalence rate of 1.2%), and typically occur within the left hemisphere middle cranial fossa or posterior fossa. Symptoms vary depending on location and size but often include headaches, weakness, cognitive changes, and hydrocephalus. We present an unusual case of a 68-year-old right-handed woman with 13 years of education who was admitted to the hospital following overdose. During a previous admission, Patient was found to have a large arachnoid cystic lesion and right-sided weakness, but was determined not to require acute intervention. Neuropsychology was consulted to assess current cognitive functioning. Method Patient was initially diagnosed with a severe major depressive episode with new-onset psychotic features following an overdose of baclofen and Tylenol. Suicide attempt was denied. Magnetic Resonance Imaging (MRI) confirmed previously identified arachnoid cystic lesion (Figure 1) causing mass effect. Patient’s MRI also revealed pituitary macroadenoma (Figure 2) that caused subtle distortion along the optic chiasm. Results The results (Table 1) suggested an abnormal cognitive profile characterized by deficits on measures of language, visuoperception, memory, and abstract reasoning in the context of relatively intact auditory attention and working memory. Conclusions The extent and severity of Patient’s deficits are likely attributable to the cystic lesion, with recent onset of visual hallucinations likely caused by location of pituitary macroadenoma. This case highlights the importance of having access to a neuropsychological inpatient consultation service to assist with clarification of symptom etiology and facilitation of appropriate diagnosis and intervention.