History A 75-year-old woman with a medical history of gastroesophageal reflux disease and type II diabetes presented to the hospital with a 3-month history of gradually worsening headaches, vague upper abdominal pain, and lower back pain. The patient denied fevers, night sweats, contact with sick individuals, occupational exposure to infection, bleeding, immunodeficiency, intravenous drug use, alcohol or tobacco abuse, history of malignancy, family history of genetic disorders, and international travel. Physical examination revealed a skin-colored mass protruding from the right side of her forehead, but there were no other notable abnormalities. Her diabetes was managed with diet, and the only prescription medication she was taking was esomeprazole. She was not taking anticoagulants. Initial laboratory work-up revealed anemia and profound thrombocytopenia (hemoglobin level, 9.4 g/dL; platelet count, 16 × 10(9)/L); these were refractory to aggressive treatment, including plasmapheresis, immunosuppression with prednisolone, and numerous transfusions. Contrast material-enhanced magnetic resonance (MR) imaging of the head was performed at admission to further evaluate the patient's headache and the mass on the patient's forehead. Ultrasonography (US) of the abdomen was performed to evaluate the cause of abdominal pain. The discovery of liver lesions at US led us to perform contrast-enhanced computed tomography (CT) of the chest, abdomen, and pelvis. Contrast-enhanced MR imaging of the abdomen was performed to narrow the diagnostic considerations for the lesions identified at CT. Bone marrow biopsy revealed no evidence of infectious or neoplastic processes. Endoscopy and colonoscopy were performed; however, they revealed no abnormalities. Further laboratory work-up included extensive testing for parasites, fungi, bacteria, and viruses, including the human immunodeficiency virus (HIV). All of the results were negative. On the 17th day of admission, the patient became acutely unresponsive, her condition deteriorated rapidly, and she died. Unenhanced head CT was performed at the time of the patient's acute decompensation.