Atypical Acute Myeloid Leukemia Presentation: Spinal Metastasis and Neurogenic Bladder

Introduction: Central nervous system (CNS) involvement in acute myeloid leukemia (AML) is rare, with symptomatic involvement is much less common, only about 1-5% of cases. We present a case of AML, with a neurogenic bladder resulting from spinal metastasis. Case Description: A 60-year-old male with AML complicated by renal dysfunction with baseline serum creatinine (SCr) 1.9-2.1 mg/dL presented with urinary retention. Diagnosed to have AML In (16) (FLT3-TKD mutation) 10 months before current presentation, treated with azacitidine & venetoclax. Admission labs were: Scr: 2.9 mg/dL, hemoglobin 9.4 g/dL, WBC count 9,300, and normal platelet count. Ultrasound: no urinary obstruction. Contrast MRI (Fig.1) showed multiple areas of white matter enhancement in the brain & diffuse T1 signal abnormalities with intramedullary lesions throughout the cervical and thoracic spine. Findings were suggestive of metastatic disease, with concern for an acute demyelinating process. Lumbar puncture results are in Tab.1 & Fig.2. A Foley catheter was placed & IV dexamethasone was started with intrathecal cytarabine, methotrexate and hydrocortisone. His urine output was 4-6 L/day, likely due to post-obstructive diuresis. Multiple voiding trials failed. Despite chemotherapy, he developed neurogenic bowel, causing diarrhea. SCr peaked at 5.6 mg/dL with acidosis. As symptoms progressed, he chose hospice care. Discussion: CNS involvement in adults with AML is rare but more common in pediatric cases, affecting 1.1% of patients. Symptoms include encephalopathy, seizures, & cranial nerve palsies. Only 1-4% present with paraspinal or intracranial granulocytic sarcoma. Risk factors include hyperleukocytosis (>105/mcL), age <2 years, elevated LDH, prominent monocytic/myelomonocytic/monoblastic characteristics, APL/PML::RARA in relapse, and molecular/cytogenetic abnormalities like FLT3-ITD, inv(16) & chromosome 11 abnormalities. Acute urinary retention in our patient is rare and not reported in adults due to intraspinal involvement by AML.