Background:Although some patients with primary brain lesions remain clinically asymptomatic, others may experience a range of symptoms, including headaches, seizures, focal neurological deficits, changes in baseline mental function, and psychiatric manifestations. Distinguishing between a primary psychiatric illness and symptoms of a primary central nervous system tumor can be especially difficult for patients with a history of mental illness. A major challenge in effectively treating patients with brain tumors is first obtaining the diagnosis.Case Report:A 61-year-old female with a medical history significant for bipolar 1 disorder with psychotic features, generalized anxiety, and previous psychiatric hospitalization presented to the emergency department with worsening depressive symptoms and without focal neurologic deficits. She was initially placed on a physician's emergency certificate for grave disability, with anticipated discharge to a local inpatient psychiatric facility once she was stabilized. A frontal brain lesion, concerning for a meningioma, was found on magnetic resonance imaging and she was instead transferred to a tertiary center for urgent neurosurgical consultation. Bifrontal craniotomy with neoplasm excision was performed. The patient's postoperative course was uneventful, and continued symptom improvement was noted at the patient's 6- and 12-week postoperative visits.Conclusion:This patient's clinical course exemplifies the clinical ambiguity associated with brain tumors, the challenge of obtaining a timely diagnosis with nonspecific symptoms, and the importance of neuroimaging for patients presenting with atypical cognitive symptoms. This case report contributes to the literature about the psychiatric manifestations of brain lesions, especially in patients with concurrent mental health disorders.