Patients in psychiatric settings may present with medical conditions, such as brain tumors, which may or may not be associated with neurological symptoms. In some cases, patients may only have psychiatric symptoms, such as mood changes (depression or mania), psychotic symptoms, panic attacks, changes in personality, or memory difficulties. Brain tumors may be detected in patients at their first presentation to mental health services or sometimes in patients with well-established psychiatric diagnoses.This article presents the case of a 29-year-old woman who was treated for >4 years for posttraumatic stress disorder and borderline personality traits, who developed depressive symptoms and memory difficulties. However, she did not develop any major neurological signs or symptoms. Brain imaging showed the presence of a left thalamic tumor, later confirmed as glioblastoma multiforme. She underwent surgical treatment and radiation therapy. With this we show that in some cases, brain tumors can be neurologically silent and only present atypical psychiatric symptoms.