Intracranial Myeloid Sarcoma: An Extremely Unusual Cause of Visual Hallucinations, Memory Loss, Personality Changes, and Depression in an Elderly Woman

Introduction/Background/Significance: Elderly patients often present with vague neuropsychiatric symptoms, posing diagnostic challenges. Myeloid sarcoma (MS) is an uncommon manifestation of acute myeloid leukemia (AML), typically found in skin, lymph nodes, and soft tissues. However, intracranial myeloid sarcoma (IMS) is extremely rare. We report the case of an elderly woman presenting with personality changes, visual hallucinations, memory loss, and depressive symptoms due to IMS.

Materials and Methods/Case Presentation/Objective: An 88 year-old woman with past medical history of JAK-2 positive polycythemia vera with transformation to AML in remission for 5 years on azacitidine + venetoclax presented with a 1-month history of paranoid complex visual hallucinations, short-term memory loss, and depressive symptoms. She denied fevers, chills, coughing, vomiting, diarrhea, or illicit drug use. Upon arrival, she was found to have normal vital signs. Neurological exam showed orientation to person and space, but not time. Deep tendon reflexes were preserved, cranial nerve function was intact. Laboratory testing was remarkable for mild leukocytosis. Urinalysis was normal. Simple tomography (CT) of the brain revealed diffuse thickening of the interventricular septum. Electroencephalogram showed slowing of the background activity in the theta range consistent with encephalopathy. Contrast-enhanced magnetic resonance (MRI) showed a 2.3 x 1.7 x 2.4 cm tumor along the septum pellucidum extending between the lateral ventricles with abnormal interventricular enhancement. Due to the proximity to the cerebral ventricles, a lumbar puncture with diagnostic cytology was performed, revealing pleocytosis of 236/mcl with 53% mononuclear cells and 83 mg/dl of protein. Flow cytometry analysis showed a 50% population of CD34+ blasts, consistent with IMS. Due to the patient's advanced age and the invasive nature of possible therapies, she preferred to undergo palliative care.

Results/Description/Main Outcome Measures: IMS represents about 0.4% of MS cases. Usual locations involve the dura, temporal lobe, cerebellum, and parasagittal regions. This patient's presentation is even more unusual given the location within the septum pellucidum. Abnormalities in this area have been associated with higher incidence of bipolar disorder, schizophrenia, obsessive compulsive disorder, and post-traumatic stress disorder, explaining the patient's marked changes in personality and complex hallucinations. This patient had relapse of AML after 5 years in remission with Venetoclax/Azacitidine, although survival at 5 years for similar patients is 5-15%. Therefore, new neurological symptoms in patients with AML should be promptly assessed with imaging, regardless of remission status. Lesions will usually appear as hyperdense on computed tomography and hypointense on T1- and T2- weighted MRI. Cell sampling with characterization of CD13, 33, 34, and 117 may be an alternative to biopsy, however results may be variable depending on cell maturation stage. Treatment options include chemotherapy and radiotherapy. Surgery is possible for debulking purposes.

Conclusions: Clinicians should maintain high suspicion for IMS in patients with AML presenting with new neuropsychiatric symptoms, regardless of remission status. Early diagnosis relies on a high level of suspicion and imaging, but biopsy may be necessary. Less invasive diagnostic tools like lumbar puncture may be used in high-risk cases. A patient-centered approach is essential in guiding treatment, particularly in frail individuals.