Abstract
A 74-year-old male presented to the emergency department (ED) with complaints of high-grade fever, productive cough, and difficulty breathing for three weeks, and a significant weight loss in the past six months. Despite a detailed investigation, diagnosis could not be achieved. Multiple empiric regimens were tried but no response was observed. Bone marrow biopsy was conducted after suspicious peripheral film result, which concluded that the patient was having myelodysplastic syndrome. Although pyrexia of unknown origin has a diverse group of diseases to evaluate for, and rare entities are difficult to diagnose, meticulous evaluation may give significant evidence for targeted diagnostic workup.